How to use laser radiative and evanescent interference fields to control movement of the sub-micron objects
Author(s):
Pavel Zemánek;
Tomáš Čižmár;
Martin Šiler;
Veneranda G. Garcés-Chávez;
Kishan Dholakia;
Věra Kollárová;
Zdeněk Bouchal
Show Abstract
We present how to use the transfer of the momentum from the spatially periodic interference field to
submicrometer-sized particles. The interference field is obtained by interference of co-propagating nondiffracting
beams and counter-propagating nondi.racting and even evanescent fields. These types of trapping fields enable
spatial organization of submicrometer-sized objects into one-dimensional arrays containing even thousands of
objects, their controlled delivery over a distance of 1 mm, their sorting according to the size of refractive index.
Moreover, the particle tracking enables to study the Brownian dynamics, jumps between neighboring optical
traps and interactions between the objects. We present a group of new experiments studying particle behavior
in such fields.
Optics of nanogratings
Author(s):
M. Foldyna;
K. Postava;
R. Ossikovski;
A. De Martino;
E. Garcia-Caurel;
B. Drevillon;
J. Pištora;
T. Yamaguchi
Show Abstract
Modeling of optical properties of nanogratings (sub-wavelength gratings) is of scientific and technological interests
for (i) application of nanogratings as new artificial effective materials with unusual optical properties and
(ii) application in non-destructive optical testing of nanogratings using optical spectroscopic ellipsometry and
polarimetry. This paper deals with anisotropic lamellar nanogratings described by Effective Medium Approximation
(EMA). Analytical formulae for effective medium optical parameters of nanogratings from arbitrary
anisotropic materials are derived using approximation of zero-order diffraction mode. The method is based on
Rigorous Coupled Wave Analysis (RCWA) combined with proper Fourier factorization method. Good agreement
between EMA and the rigorous model is observed, where slight differences are explained by the influence
of higher Fourier harmonics in the nanograting. Analytical spectral formulae for ordinary and extraordinary
effective optical functions are derived for nanogratings consisting of material described by Sellmeier, damped
harmonic oscillator, and Drude formulae. Spectral origin for birefringence of dielectric nanogratings and linear
dichroism for absorbing ones is discussed.
How optics has changed data communications
Author(s):
Ivan Glesk;
Paul R. Prucnal
Show Abstract
Today's voice/data communication packet or circuits switched networks are characterized by hybrid architectures. The
relatively low transmission bandwidth of electronics and optoelectronic interfaces makes it difficult to fully utilize the large
bandwidth of optical fiber. This problem can be overcome if the data is left in optical form during signal processing steps
such as address recognition, demultiplexing, switching, routing, regeneration, dispersion compensation, and clock recovery.
This requires high bandwidth, ultrafast, all-optical devices to perform these signal processing functions. These will allow
move away from electronic bandwidth of a few tens of gigahertz to a terahertz bandwidth offered by all-optical devices thus
fully utilize the enormous capacity of an optical fiber. This requires new data formats as well as a whole new class of
ultrafast all-optical devices. We will describe a new generation of such devices based on different optical phenomena such
as wavelength filtering, phase shifting, optical interference, mixing, and controlled nonlinear index changes which enable us
to perform various very complex functionalities not only in today's networks but also for the future use in all-optical data
networks.
Cavity ring down and vacuum UV spectroscopy: applications for radical absolute density measurements in plasma
Author(s):
Pavel Veis;
Peter Macko;
Juraj Jašik
Show Abstract
Survey of several experimental techniques applied for absolute density measurements of atoms and radicals in plasma is
presented. It includes the Vacuum Ultraviolet Absorption Spectroscopy, Actinometry and Emission Spectroscopy, Laser
Absorption Spectroscopy and highly sensitive Cavity Ring-Down Spectroscopy. Performances and operation
procedures of these techniques are illustrated.
The photorefractive effect in LiNbO3 crystals
Author(s):
Ivan Turek;
Norbert Tarjányi
Show Abstract
The contribution presents results of the experimental investigation of the photorefractive effect in LiNbO3 crystals obtained
from light diffraction observed on photorefractive records of periodic optical field and obtained from interference images of
refractive index modulation in the records. These results are compared with results following from equations describing the
process of the photorefractive record formation in cases when various mechanisms of generation of the internal electric
current responsible for photorefractive effect are taken into account. The comparison between the calculated and measured
dependences shows that the modulation of the refractive index is not caused by
the electro-optical effect (as the standard model assumes) but by the redistribution of carriers trapped at the donor centres and
by change of their polarisability.
Orbital angular momentum of mixed vortex beams
Author(s):
Z. Bouchal;
V. Kollárová;
P. Zemánek;
T. Čižmár
Show Abstract
The orbital angular momentum (OAM) of the single vortex beam depends on its power and wavefront helicity. In the
paper, this relation is generalized for mixed vortex beams composed of several coaxial vortices with different topological
charges. The presented interference law indicates interference effects of the OAM resulting in local spatial gradients of the
OAM density. Description of the OAM of mixed vortex beams is used for demonstration of a possibility to tune the OAM
density of a composite vortex field without changing topological charges or intensity distribution. Experimental realization
of the OAM tuning is discussed for interference of two focused vortex beams generated by means of a spiral phase mask.
Characteristic matrix of anisotropic coupling gap
Author(s):
Jaromír Pištora;
Jaroslav Vlček;
Roman Antoš;
Tomuo Yamaguchi;
Kamil Postava;
Ondřej Bárta
Show Abstract
The characteristic matrix T and total matrix M have been determined for isotropic prism coupling gap and anisotropic
one with magnetic ordering in linear magneto-optical approximation. On the base of these matrices the reflection and
transmission coefficients of structure have been specified. The effect of gap thickness, index of refraction and linear
transverse anisotropy of coupling media is discussed. Special attention is devoted to the ultra-thin approximation.
What is it optical binding and how to study this phenomena
Author(s):
Vítězlav Karásek;
Pavel Zemánek
Show Abstract
Optical binding uses the fact that each object placed into the optical field modifies this field and at the same time
interacts with other objects in the field. Under certain circumstances these objects can self-organize and create
so called "optically bound matter". This happens for various sizes of particles and therefore there is no unique
method for the theoretical description of the phenomena. If the objects are small compared with wavelength
then they can be approximated as single dipoles. On the other hand paraxial wave theory is acceptable for
particles with sizes in multiples of the wavelength. We develop a method based on coupled dipole method
(CDM) or also known as a discrete dipole approximation (DDA). This numerical method covers the range of
sizes when particles are comparable or smaller then wavelength. For some cases the comparison with paraxial
wave theory is also possible. Our aim is to specify conditions suitable for creation of optically bound systems
which are experimentally verifiable.
Reconstruction of the wave tilt and orientation of tilt axis using OVI
Author(s):
M. Borwińska;
A. Popiołek-Masajada;
B. Dubik
Show Abstract
In this work the application of the Optical Vortex Interferometer (OVI) to small-angle rotation measurements is
presented. OVI is based on the regular net of optical vortices. In our experimental setup a regular net of optical vortices
is produced by the interference of three plane waves. Distortion of one, two or three of the interference waves results in
a characteristic vortex net deformation. This deformation can be measured and related to the physical quantities being
investigated. In the given paper we present the ability of the OVI to measure the deflection angle of the wave vector and
its orientation in a single measurement. Two different methods which allow for comparing the geometry of the vortices
net were used to analyze the results of the experiment. They were compared with the method based on the standard two
beam interferogram analysis. The results show that the OVI system can be successfully used to measure the deflection
and orientation of the wave vector. The vortex methodology is more accurate than classical two beam interferometry in
the case of the rotation angles in the range of few arcseconds.
Design and testing of the phase mask for transfer of information by vortex beams
Author(s):
Radek Čelechovský;
Zdeněk Bouchal
Show Abstract
In the paper, design of the phase-only mask enabling generation of variable superpositions of vortices is described and
analyzed. A variability of the generated mixed vortex field is achieved by intensity modulation of an array of point sources
illuminating the mask. A usability of the vortex superpositions for information encoding, transfer and decoding is also
demonstrated. The optical setup prospective for application in free-space communications is proposed and experimentally
tested.
Two generation modes of a laser diode module
Author(s):
Dagmar Senderáková;
Anton Štrba;
Vladimír Mesároš
Show Abstract
The contribution follows our previous works, dealing with study of the coherence properties of laser diode modules
(LDM) and considering possibility to use them for the purposes of coherent optics. A better external thermal
stabilisation unit, based on the Peltier effect, was developed. A holographic grating, produced at our laboratory, enabled
us to accomplish LDM spectrum analysis and get results that are more accurate than those, obtained in our previous
works. The possibility and properties of both, mono and two frequency LDM generation modes are presented.
Axial diffraction patterns in the vicinity of the focus of the off-axis holographic diffractive collimator
Author(s):
Milan Hradil;
Miroslav Miler;
Jan Pala
Show Abstract
Off-axis holographic optical elements can be used for collimation of optical beams from edge emitting diode lasers.
Such a single element collimator can simultaneously compensate large elliptic cross-section and considerable
astigmatism of that beams and also reduce two selected lower aberrations. Beside a current transverse diffraction pattern
in the focus also patterns in the vicinity of the focus should take attention. Diffraction patterns due to an elliptic aperture
of such a collimator are very complicated and for their theoretical description sophisticated methods must be used. This
contribution involves some preliminary results of the study. Theoretical transverse diffraction patterns in the vicinity of
the focus have been mainly presented and their description analyzed.
Polarizing photonic crystal fibers for different operation range
Author(s):
G. Statkiewicz;
M. Szpulak;
T. Martynkien;
W. Urbanczyk;
J. Wojcik;
M. Makara;
P. Mergo;
T. Nasilowski;
F. Berghmans;
H. Thienpont
Show Abstract
We have experimentally characterized three polarizing photonic crystal fibers manufactured by the Laboratory of Optical
Fiber Technology, Maria Curie-Sklodowska University, Lublin, Poland. In the investigated structures the dissimilarity in
the cut-off wavelengths is induced by a pair of large air holes adjacent to the fiber core. Because of different geometry,
the investigated fibers have different polarization ranges. In the first structure, the polarization dependent loss (PDL) of
3 dB/m is observed at 1300 nm and further increases against wavelength. In the two other fibers, the polarization
bandwidth is shifted towards longer wavelengths. We have also investigated the effect of bending on polarization
characteristics. It was experimentally demonstrated that for bent fiber the attenuation of the LPy
01 increases for shorter
wavelengths, which results in wider polarization bandwidth. Moreover, we have numerically analyzed and optimized for
maximum operation bandwidth two constructions of the index guided PCFs, whose polarization properties are induced
by unequal diameters of the cladding holes.
Optical gain in planar waveguides
Author(s):
T. Ostatnický;
P. Janda;
J. Valenta;
I. Pelant
Show Abstract
Description of optical waveguides is commonly restricted to propagation at distances much larger than the width of the
waveguide core and therefore only guided modes are taken into account in theory. Effects connected with leaking of the
waves into the substrate may be, however, very important for possible applications in microelectronics. In this paper, we
overview our model of photoluminescence of an active planar waveguide and we extend it in order to describe mode
formation during propagation in the waveguide. We also include optical amplification into our model and derive
formula for description of the Variable Stripe Length (VSL) method widely used for measurement of the net gain
coefficient. We demonstrate necessity for corrections of VSL results since their straightforward interpretation may be
misleading.
Adaptively controlled supercontinuum generation in a microstructure fiber
Author(s):
D. Lorenc;
D. Velic;
F. Uherek;
A. N. Markevitch;
R. J. Levis
Show Abstract
Efficient confinement of laser radiation in the core of a photonic crystal fiber (PCF) enhances the nonlinear processes
resulting in supercontinuum generation. The technique of adaptive pulse shaping using an evolutionary algorithm
provides a method to gain control over nonlinear processes. Adaptive pulse shaping of the driving laser radiation
passing through the photonic crystal fiber was employed to modify the shape and composition of the output
supercontinuum. Amplified pulses of a Ti:Sapphire laser system were coupled into a high air fill factor (cobweb) PCF
sample. Alternatively a Cr:Forsterite master oscillator was used as the pump source. Supercontinua acquired with
unshaped pulses are compared for both pump sources. Amplitude and phase shaping of the amplified Ti:Sapphire pulses
was then used to optimize the emission between 500 and 700 nm, as well as a soliton centered at 935 nm. The originally
separated spectral regions near 700 nm eventually merged into a smoother and broader supercontinuum. The intensities
of the broadband emission and of the soliton driven by a shaped laser pulse increased in comparison to unshaped pulses
by factors of 4 and 3, respectively. In addition, the suppression of self-steepening effects in supercontinuum spectra was
demonstrated using a shaped laser pulse.
Dispersion measurements of anisotropic materials and a new fiber-optic sensor configuration
Author(s):
R. Chlebus;
P. Hlubina;
D. Ciprian
Show Abstract
We present two different white-light spectral interferometric techniques employing a low-resolution spectrometer
for a direct measurement of the group dispersion of anisotropic optical materials. First, the dispersion of the
group birefringence of a calcite crystal is measured in a tandem configuration of a Michelson interferometer and
the calcite crystal. Second, the dispersion of the ordinary and extraordinary group refractive indices of a quartz
crystal is measured in a Michelson interferometer with the crystal inserted in one of the interferometer arms. Both
techniques utilize the spectrometer to record a series of spectral interferograms for measuring the equalization
wavelength as a function of the displacement of the interferometer mirror from the reference position, which
corresponds to a balanced Michelson interferometer. We confirm that the measured group dispersions agree well
with those resulting from the semiempirical dispersion equations. Furthermore, we propose a new white-light
spectral-domain fiber-optic sensor configuration utilizing a tandem configuration of a uniaxial (calcite or quartz)
crystal and a sensing birefringent fiber.
Intermodal interference in photonic crystal fibers
Author(s):
I. Turek;
D. Káčik;
J. Canning;
I. Martinček;
N. Issa
Show Abstract
The equipment for intermodal interference investigation is described. The results of an investigation of intermodal
interference within a photonic crystal fibre (from Centaurus Technologies, Sydney) in terms of length and frequency
region are presented. From the measured values the difference of the phase constant of the fundamental and the first
higher order (antisymmetric) modes, as well as the decay constant of the mode in the wavelength region exceeding the
two modes region, are determined.
Manufacturing of extremely narrow polymer fibers by non-diffracting beams
Author(s):
Jan Ježek;
Tomáš Čižmár;
Pavel Zemánek
Show Abstract
We present an experimental way how to produce extremely narrow polymer fibers using photopolymerization. Such fibers
solidify in the high intensity regions of nondiffracting zero-order Bessel beam from the solution of UV cured resin. Bessel
Beams are particularly suitable for this purpose because of their narrow high intensity core and long axial region of uniform
intensity. The width of the created polymer fiber is strongly dependent on the properties of the Bessel beam, used laser
power and curing time. Fibers wide 2 μm were created and their length exceeded 1 cm. This length several times exceeded
the axial region of the Bessel beam existence due to self-writing waveguide mechanism.
Workplace for manufacturing devices based on optical fiber tapers
Author(s):
Tomáš Martan;
Pavel Honzátko;
Jiři Kaňka;
Karel Novotný
Show Abstract
Many important optical fiber components are based on tapered optical fibers. A taper made from a single-mode optical
fiber can be used, e.g., as a chemical sensor, bio-chemical sensor, or beam expander. A fused pair of tapers can be used
as a fiber directional coupler. Fiber tapers can be fabricated in several simple ways. However, a tapering apparatus is
required for more sophisticated fabrication of fiber tapers.
The paper deals with fabrication and characterization of fiber tapers made from a single-mode optical fiber. A
tapering apparatus was built for producing devices based on fiber tapers. The apparatus is universal and enables one to
taper optical fibers of different types by a method utilizing stretching a flame-heated section of a silica fiber. Fiber
tapers with constant waist length and different waist diameters were fabricated. The transition region of each fiber
taper monotonically decreased in diameter along its length from the untapered fiber to the taper waist. The fiber tapers
were fabricated with a constant drawing velocity, while the central zone of the original single-mode fiber was heated
along a constant length. The spectral transmissions of the manufactured fiber tapers with different parameters were
measured by the cut-back method.
The optical vortex interferometer AD 2006
Author(s):
Jan C. Masajada
Show Abstract
The optical vortex interferometer (OVI) is based on the regular net of optical vortices, which are generated by the
interference of three plane waves. In this paper the current state of the OVI is described. The paper starts with an outline
of the OVI theory. In the next step the three different versions of the optical body of OVI are shortly described. The
possible enhancements of the instrument are also discussed Next the methods for interfergoram analysis are presented
and the possible applications of the OVI are listed and shortly discussed.
In vitro dynamic observations in a low-coherence holographic microscope
Author(s):
Pavel Kolman;
Hana Janečková;
Radim Chmelík;
Pavel Veselý;
Luděk Lovicar;
Zdeněk Foret
Show Abstract
The paper refers about the main characteristics of low-coherent holographic imaging in transmitted light, like optical
sectioning, optical path differences (OPD) measurement and high frame rate imaging. To demonstrate the optical
sectioning property of the microscope, we performed the measurement using laser as a coherent light source and
a halogen lamp with interference filter as a low-coherent light source. We observed the same place of the model sample
uncovered and then covered with a volume diffuser.
Compact laser tweezers
Author(s):
Mojmír Šerý;
Zdeněk Lošťák;
Milan Kalman;
Petr Jákl;
Pavel Zemánek
Show Abstract
In this article we present laser diode based tool for optical manipulation with microobjects. This tool is very
suitable for micromanipulations with large spectrum of speciments in the diameter range 0.5 - 30 μm. Adapter
is directly mounted to the microscope without any aditional improvements and fits to many comercially available
microscopes. Key feature of this adapter is compactness, usability and simple handling. With this adapter
user takes advantage of wide spectrum of comercially available laser diodes with different wavelengths. For this
reason the tool can be used in many areas such as biology, medicine and measurements.
Aluminum laser welding optimization
Author(s):
Hana Chmelíčková;
Viktor Halenka;
Hana Lapšanská;
Martina Havelková
Show Abstract
Pulsed Nd:YAG laser with maximal power 150 W is used in our laboratory to cut, drill and weld metal and non-metal
thin materials to thickness 2 mm. Welding is realized by fixed processing head or movable fiber one with beam diameter
0,6 mm in focus plane. Welding of stainless and low-carbon steel was tested before and results are publicized and used in
practice. Now the goal of our experiment was optimization of process parameters for aluminum that has other physical
properties than steels, lower density, higher heat conductivity and surface reflexivity. Pure alumina specimen 0,8 mm and
Al-Mg-Si alloy 0,5 mm prepared for butt welds. Problem with surface layer of Al2O3 was overcome by sanding and
chemical cleaning with grinding paste. Critical parameters for good weld shape are specimen position from beam focus
plane, pulse length and energy, pulse frequency and the motion velocity that determines percentage of pulse overlap.
Argon as protective gas was used with speed 6 liters per second. Thermal distribution in material can be modeled by
numerical simulation. Software tool SYSWELD makes possible to fit laser as surface heat source, define weld geometry,
and make meshing of specimen to finite elements and compute heat conduction during process. Color isotherms, vectors,
mechanical deformations and others results can be study in post-processing.
Chamber with controlled atmosphere for fluorescence measurements in the project AIRFLY
Author(s):
Libor Nožka;
Václav Vacek;
Michal Doubrava;
Miroslav Hrabovský;
Jan Řídký;
Petr Schovánek;
Miroslav Palatka;
Martina Boháčová;
Miroslav Pech;
Dušan Mandát
Show Abstract
The aim of the AIRFLY (air fluorescence yield) project is to simulate and to measure the process of the
fluorescence and Cherenkov emission produced by impact of cosmic rays on molecules of nitrogen in high level
atmosphere. Several setups were designed to measure fluorescent and Cherenkov light. We report the chamber with
controlled atmosphere to simulate conditions in various levels of the Earth atmosphere. The chamber was designed in
the Institute of Physics of Academy of Sciences of the Czech Republic in cooperation with the Faculty of Mechanical
Engineering, Czech Technical University and the Joint Laboratory of Optics of Palacky University and Institute of
Physics of Academy of Sciences in Olomouc.
Primary length standard adjustment
Author(s):
Robert Ševčík;
Jana Guttenová
Show Abstract
This paper deals with problems and techniques connected with primary length standard adjusting, which includes
disassembling of the device and by use of the secondary laser with collimated beam and diffraction laws successively
reassembling of the laser. In the reassembling process the device was enhanced with substituting the thermal grease
cooling of cold finger by copper socket cooler. This improved external cooling system enables more effective cooling of
molecular iodine in the cell, which allows better pressure stability of iodine vapor and easier readjustment of the system.
New three-dimensional configuration of multidirectional phase tomograph
Author(s):
Martin Antoš
Show Abstract
A three-dimensional configuration of multidirectional Mach-Zehnder holographic interferometer with diffusive illumination
is used in novel phase tomograph. The multidirectional tomography setup with diffusive illumination enables to digitize
many times higher number of projections in comparison with other known configurations. This setup doesn't require to
rotate with the object. The resulting resolution of the reconstructed three-dimensional image depends not only on the choice
of computer tomography algorithm, but first of all on the device ability to digitize sufficient number of complete and
equally spaced projections in given angular range with low noise level. The proposed paper is focused on design and
optimization of the optical tomography setup for the three-dimensional non-contact diagnostic of the physical properties of
stationery placed non-symmetric phase objects. Optimization of geometrical configuration design of multidirectional
holographic interferometr, with respect to significant increase of the signal to noise ratio in interferograms is performed.
Characteristic properties of the multidirectional interferograms of investigated phase objects are discussed and presented.
Proposal of the 1m laser interferometer modification in the Slovak Institute of Metrology
Author(s):
Ján Bartl;
Roman Fíra
Show Abstract
This contribution deals with new design of the SMU 1m interferometer for the calibration of long gauge blocks, which is
intended to be realized in next few years. Its scheme is based on the current design built 25 years ago and the main goal
is to eliminate some significant sources of the measurement error and uncertainty. Three alternatives are indicated. They
can be realized subsequently in order to avoid a longer period between dismantling of a current scheme and installation
of the new one.
Avalanche photodioide as two photon correlation detector
Author(s):
Josef Blazej
Show Abstract
The future possibility of single photon counters development is presented. The solid state photodetectors based on
silicon avalanche photodiode has been optimized for detection of echo signal in millimeter laser ranging measurements.
The structures are up to 200 um in diameter, they exhibit an excellent uniformity of detection delay, sensitivity and
timing resolution. The avalanche process nonlinearity enhance the influence of starting conditions to avalanche grow
rapidity. This is the reason why the internal delay of this type of detectors is depended on detected signal intensity, i.e.
in case of weak signal depended on number of detected photons. The dependence is in the range of 0-200 ps for photon
numbers 1-1000 photons. The active quenching and gating circuit with time walk compensation has been constructed to
eliminate this effect. We have used the outputs of the compensation circuit to estimate the photon numbers detected on a
shot by shot basis. The mutual time difference between the compensated and uncompensated output pulses corresponds
to the photon number. Monitoring this time difference by the Pico Event Timer with picosecond timing resolution
enabled to monitor the echo signal strength fluctuation on a shot by shot basis in laser ranging experiments. The goal in
the field of correlation detection is to enhance the primary delay dependence and to use it for initial photon number
discrimination. The experimental status quo will be presented.
Theory of chromatic sensor for topography measurements
Author(s):
Antonín Mikš;
Jiří Novák;
Pavel Novák
Show Abstract
The problems of topography of surfaces are very important in various parts of science and engineering. Several
approaches exist for measurement of surface figure and roughness. Measurement methods can be divided into two
distinct categories, contact and non-contact techniques. Our work describes a relatively simple method for topography
measurements that uses special optical systems (hyperchromats) with a linear dependence of longitudinal chromatic
aberration on the wavelength of light. The aim of this work is to show a possible application of hyperchromatic optical
systems for topography of surfaces. The work describes the theory for calculation of design parameters of
hyperchromats, i.e. optical systems with large longitudinal chromatic aberration that is in our case linearly dependent on
the wavelength of light. On the basis of the performed analysis, such optical systems (chromatic sensors) can be
designed that permit to perform measurements of topography of surfaces, i.e. determine a figure or roughness of
surfaces. The described theory makes possible to design the chromatic sensor with the required measurement accuracy
and dynamic range. The sensor uses polychromatic light and relatively simple experimental arrangement. The proposed
measurement technique seems to be quite simple and cost effective with respect to other measurement methods.
Calibration and topographic and profilometric methods using the prism normal measurement
Author(s):
Tomáš Rössler;
Michal Pochmon;
Dušan Mandát;
Miroslav Hrabovský;
Jana Matušová
Show Abstract
The presented paper is dealt with the calibration of methods of the optical 3D measurement of the shape of objects.
Methods can be divided into the two groups: topographic and profilometric methods. The topography is a method
giving a contour map as result. On the other hand, the result of the profilometry is the data file containing the
topographic depth (z-axis value) in the regular or irregular network of points (they are given by the x-axis and y-axis
values). Every method needs the calibration of these values that means the relation between measured and resulting
quantity. The x-axis and y-axis values are obtained as pixel distances from the record of optical image by the CCD
camera. The z-values are computed by various ways in dependence of the calibrated method character. It can be the
fringe orders, pixel distances again, phase differences or others. The paper describes the procedure of determination of
calibration constants. It is based on the known object measurement by the calibrated method and the following
evaluation of results.
Dispersion measurements of a birefrigent holey fiber using white-light spectral interferometry
Author(s):
D. Ciprian;
P. Hlubina;
J. Trojková
Show Abstract
We present white-light spectral interferometric techniques for measuring dispersion characteristics of a birefringent
holey fiber supporting two lowest-order linearly polarized (LP) spatial modes. The first technique utilizes
a low-resolution spectrometer at the output of a tandem configuration of a Michelson interferometer and the
holey fiber to measure the equalization wavelength as a function of the optical path di.erence adjusted in the
interferometer. Thus we measured the dispersion of the group modal birefringence for the LP01 and even LP11
spatial modes and the intermodal group dispersion for two orthogonal polarizations of the LP modes. We present
also a new technique for measuring the differential group refractive index dispersion of the holey fiber which is
inserted in one of the arms of a Mach-Zehnder interferometer. The technique is based on measuring the equalization
wavelength as a function of the displacement of the interferometer mirror from the reference position,
which corresponds to a balanced Mach-Zehnder interferometer.
Dispersive white-light spectral interferometry used to measure thickness of a thin film on a substrate
Author(s):
P. Hlubina;
D. Ciprian;
J. Luňáček;
M. Lesňák;
R. Chlebus
Show Abstract
We present a white-light spectral interferometric technique for measuring the thickness of a thin film on a
substrate. First, the spectral interferogram is expressed analytically for a setup of a slightly dispersive Michelson
interferometer with a cube beam splitter and a fiber-optic spectrometer of a Gaussian response function when
one of the interferometer mirrors is replaced by the thin film on the substrate. We reveal that the visibility of
the spectral interference fringes is dependent on the reflectance of the thin-film structure and that the phase
change on reflection from the structure is inscribed in the phase of the spectral interference fringes. We model
the wavelength dependences of the reflectance and of the so-called nonlinear phase function for SiO2 thin film on
a silicon wafer of known optical constants taking into account multiple reflection within the thin-film structure.
Second, we perform experiments with the SiO2 thin film on the silicon wafer and record the spectral interferograms
for determining the thin-film thickness. We confirm very good agreement between theory and experiment and
determine precisely various thicknesses of the SiO2 thin film.
Small area curvature measurement
Author(s):
Jan Hošek
Show Abstract
This article presents an optical set-up for liquid meniscus planarity measurement at the small capillary tip, which is based
on geometric optics principle instead of much more expensive phase shift interference methods. The theoretical study of
the meniscus planarity measurement with different geometrical optical set-up is presented. The influence of the set-up
alignmen*t errors is also presented. On theses bases has been designed and developed an optical set-up for the
measurement of meniscus planarity at the 0,3 mm diameter capillary tip. Necessary radius resolution for the surface
tension of liquid measurement was determined and verified the set-up fulfills this condition.
Moiré deflectometry used for refractive index measurements
Author(s):
J. Keprt;
L. Bartoněk
Show Abstract
To describe the optical characteristics of phase object the moire deflectometry system can be used. A Talbot
interferometer is constructed with two gratings placed in a collimated beam of light. The moire fringes are generated by
superimposing the self-imaged grating in Talbot plane with the second reference grating (of the some period or near the
some period as the first one). If the phase object is placed on front of the first grating, the light deflected by the object
yields the shifted Talbot images and the resultant moire fringes show the change of the refractive index of the phase
object. This method can be also used for measurement of the refractive index of lenses as well as liquids and gases
showing self-focusing and self-defocusing effect. Computerized video-image than enables observation and evaluation of
changes of moire fringes practically in real-time. In comparison with other interferometric methods the advantages of
the moire deflectometry technique are its extreme experimental simplicity, low cost and low sensitivity to external
disturbances.
Comparative studies of water turbidity on the grounds of a nephelometric method and diffraction effects
Author(s):
Józef Kirkiewicz;
Barbara Pawlak;
Bohdan Bieg;
Ryszard Pikuła;
Piotr Treichel;
Bożena Mikłaszewicz;
Jadwiga Mrozek-Lejman
Show Abstract
Water turbidity may be examined by measuring the scattered light intensity by suspended particles in comparison with
the scattered light intensity in pattern solution that states for a nephelometric method. Water turbidity may be also
measured with the use of monochromatic light beam absorption. But a diffraction method has found the broadest use.
The method uses indicatrix of scattering as the sizes of the measured particles vary from 0.1 to 2000 μm. The
examinations of the Odra River water turbidity have been performed on the basis of a diffraction method. Results of the
examinations are plotted in graphs.
Investigation of the relations between the dust granularity and pollution concentration
Author(s):
Józef Kirkiewicz;
Janusz Chrzanowski
Show Abstract
Mechanism of light interaction with particles of dusts was presented in quantum aspect by analyzing differential
cross section onto scattering. For rotational symmetry the differential scattering cross section was related with angle of
scattering. One pointed on relation between the shape of indicatrix of scattering with size of scattered particles. Next a
model of devices was introduced which makes possible a measurement of concentration of dustiness of the air oe gases
and defines the sizes of dust grains on the basis of measurement of the scattered light stream.
The estimation of suspension concentration in the Odra River waters by LALLS method
Author(s):
Józef Kirkiewicz;
Piotr Treichel;
Jadwiga Mrozek-Lejman;
Bożena Miklaszewicz;
Bohdan Bieg;
Barbara Pawlak
Show Abstract
Law-angular laser light scattering method (LALLS), using Rayleigh criterion as well as Mie method, allows one to
investigation of suspended particles within the range of 0.1 to 2000 µm of their sizes when the refractive index of the
suspended matter as well as the dispersing medium are known. The method bases on the fact that the diffraction angle is
inversely proportional to the size of a suspended particle. The advantage of the method is direct and quick measure of the
volume distribution of the suspended particles.
LALLS method was used here to estimate the volume concentration of suspension in the Western Odra River waters.
Some factors that affect the surface measurement accuracy of a low-coherence interference microscope
Author(s):
Luděk Lovicar;
Radim Chmelík;
Jiří Komrska;
Veronika Matoušková;
Pavel Kolman;
Zdeněk Foret
Show Abstract
Low-coherence interference microscopy (LCIM) is a powerful imaging high-accuracy technique for surface inspection
and profiling. The principle of this technique is based on the interference of two waves with the use of incoherent light,
usually of halogen lamp or superluminescent diode. One of its principal advantages is that both the image intensity and
the image phase may be extracted from the output signal. The image phase may be converted subsequently into the
surface height data. The image intensity is depth discriminated in a similar way as in the confocal microscopy. A
limited lateral resolving power of the microscope significantly influences the accuracy of profiling with LCIM. This
factor affects not only the image intensity of the reconstructed signal, but also behaviour of the image phase. It could
result in an error in surface-height data measurement, especially if the structure contains details, the size of which is
comparable with the resolving power of the microscope. This paper deals with the deviation of measurement of one-dimensional
and two-dimensional periodic surface structures in relation to the numerical aperture of the objective lens
and to the spectral composition of the illumination. The calculations are based on the polychromatic coherent transfer
function, which describes the influence of temporal and spatial coherence of illumination on the imaging characteristics
of the LCIM. Experiments were done with the reflected-light low-coherence holographic microscope.
Validation of 3D profilometry using total knee artroplasty samples
Author(s):
Dusan Mandat;
Tomas Rössler;
Miroslav Pech;
Miroslav Hrabovsky;
Libor Nozka;
Michal Pochmon;
Jiri Gallo
Show Abstract
This article treats of using the 3D optical scanning topography as one of possible methods of an analysis of the cotyle
deformation. The object of this experiment is to quantify the decrease of cotyle material. The scanning object is
polyethylene coxa cotyle ABG I. We compare two identical coxa cotyle. One of them is artificially involved to simulate
a real using. We calculate material decrease of these cotyle, and then we compare the result with simulation and the
result of gravity surveying.
Application of Shack-Hartmann wavefront sensor for testing optical systems
Author(s):
Jiri Novak;
Pavel Novak;
Antonin Miks
Show Abstract
Our work deals with a method of measurement of the wavefront shape using the lenslet array objective based on the
Shack-Hartmann method. An analysis and computer simulation was carried out for the designed wavefront sensor,
devoted to optical testing applications. The obtained accuracy is comparable to common interferometric techniques in
optical industry, and it is sufficient for testing of optical elements and systems. Our work focuses on an application of
the sensor for image quality testing of optical systems and measurement of centricity of optical systems. Several
experiments were made for testing optical systems in UV and visible spectrum using the wavefront sensor, which
verified the reliability and accuracy of the sensor for the case of optical system testing in optical industry.
Spatial coherence profilometry
Author(s):
Pavel Pavlíček;
Zhihui Duan;
Mitsuo Takeda
Show Abstract
Spatial coherence profilometry is a method for measurement of the geometrical form of objects. In addition to the
two lateral coordinates x and y, it measures the longitudinal coordinate z. In this way the complete 3D description
of the object's surface is acquired. The main piece of the presented method is a Michelson interferometer illuminated
by a monochromatic spatially extended light source. The surface of the object whose geometrical form should be
measured is used as one mirror of the Michelson interferometer. By moving of the measured object along the optical
axis, the intereference is observable only if the object's surface occurs in the vicinity of the so-called reference plane.
The reference plane is given by the position of the object mirror when the Michelson interferometer is balanced. The
described effect follows from the form of the spatial coherence function originated by the spatially extended light
source. If the intensity at the output of the interferometer is recorded as a function of the position of the measured
object, a typical correlogram arises. This correlogram is similar to that known with white-light interferometry. From
the maximum of the correlogram, the z coordinate of the object's surface can be determined. Usually a CCD camera
is used as the detector at the output of the Michelson interferometer. Then z coordinates of many surface points are
parallel measured in the course of one measurement procedure and the 3D description of the object's surface is acquired.
The scanning in the lateral direction is not necessary. Thus the described method provides a spatial coherence analogy
to white-light interferometry which is based on temporal coherence. Unlike white-light interferometry, the described
method does not require a broadband light source, the interferometer is illuminated by a monochromatic light source,
usually a laser.
The estimation of suspension concentration in natural waters by means of selected optical methods
Author(s):
Barbara Pawlak;
Józef Kirkiewicz;
Jadwiga Mrozek-Lejman;
Radosław A. Gąsowski;
Waldemar Staroń;
Bożena Mikłaszewicz;
Janusz Mielnik;
Zbigniew Safaryn
Show Abstract
Knowledge the suspension concentration is basic for realisation of the ecological as well as technical purposes in a water
area but its direct measurement is difficult.
In the paper the authors present the estimation methods of volume suspension concentration in natural waters when the
function of dispersion distribution of size parameter is known and unknown and the light attenuation coefficient of the
suspended matter is known, too.
The measure of the total concentration or the concentration considering only the large suspended particles may be a
useful comparative device for different water areas as for the quantitative and statistical structure of the suspended matter
in their waters.
Shape measurement method of concave mirrors
Author(s):
Miroslav Pech;
Miroslav Hrabovský;
Petr Schovánek;
Dušan Mandát;
Libor Nožka
Show Abstract
The theory, optical, mechanical, and software design for a special Hartmann wavefront analyzer is presented. This
method is applied for the non-contact method of concave mirrors shape measurements. The so-called Hartmann test is
used with the digital image reading and the fast computer data evaluation. In this method a small mask with several holes
is used. Holes are radially positioned. The wavefront sensor measures a tilt of the wavefront or the mirror surface. The
tilt measurements are then converted into a replica of the wavefront by performing a form of integration called wavefront
reconstruction. Our institute Joint Laboratory of Optics produces segmented mirrors for the Pierre Auger observatory
fluorescent detector. We use this method as the qualitative measuring of this spherical mirror segments. These segments
are unique because they are light and ultrathin. The production of mirrors is based on standard operations commonly
used in the optical industry (cutting, drilling, milling, grinding and polishing), with the difference that they are extremely
thin. This fact can cause segment shape instability in the production process. This method objectively defines the shape
and specifies the difference of the segment shape from an ideal surface in micrometer accuracy.
Verification of abrasion measurement of juncture implants using Fourier profilometry
Author(s):
Michal Pochmon;
Tomáš Rössler;
Dušan Mandát;
Jiří Gallo;
Miroslav Hrabovský
Show Abstract
Three dimensional measurements have great use today and it is quite large and important part of the experimental
physics. These methods are also used in biomedicine for measuring the abrasion of juncture implants, coxal cotyles and
knees. These implants are under stress in the patient's body and therefore they change their shape and waste some
material. This waste is a key parameter for examination of quality of the given type of implant. The surface of the used
implant is measured and compared with unused one. This comparison gives possibility to enumerate the waste of
material of implant. One of the three dimensional optic measurement methods is Fourier profilometry, based on the
analysis of harmonic structure projected on the surface of the measured object. It is profilometric method; it means that
the surface of measured object is specified in every point of result. Fundamentals of Fourier profilometry, its features
and used experimental setup are described in the beginning of the paper. The results of such measurement lead to
enumerate the waste of material of implant. The purpose of this contribution is the verification of used method to
measure the waste of material of implant. Its principle lies in artificial abrasion made by cutting tool, so the abrasion is
defined and known. The surface of the implant is measured before and after this machining and the waste of material of
implant is enumerated. This value is compared with an actual waste of material.
Parallel plate testing using the optical vortex interferometer
Author(s):
Agnieszka Popiołek-Masajada;
Bogusława Dubik
Show Abstract
Optical Vortex Interferometer (OVI) is a new type of interferometer which is based on the regular net of optical vortices. Optical vortices (OV) are the point like phase singularities. The point where the phase is undetermined is called the vortex point. In OVI the net is generated by the interference of three plane waves. There might be different application of such an instrument. It can be used to small-angle wave rotation measurements and to the orientation of the tilt axis. The resolution of the instrument is on the level of well known and tested classical interferometric methods. We expand the algorithms described in our previous articles to the testing of the parallel plates.
Optical analysis of suspended particles in the cerebrospinal fluid obtained by puncture from patients diagnosed with the disorders of cerebrospinal fluid (CSF) circulation
Author(s):
Waldemar Staroń;
Leszek Herbowski;
Henryk Gurgul
Show Abstract
The goal of the work was to determine the values of cumulative parameters of the cerebrospinal fluid. Values of the parameters characterise statistical cerebrospinal fluid obtained by puncture from the patients diagnosed due to suspicion of normotensive hydrocephalus.
The cerebrospinal fluid taken by puncture for the routine examinations carried out at the patients suspected of normotensive hydrocephalus was analysed.
In the paper there are presented results of examinations of several dozens of puncture samples of the cerebrospinal fluid coming from various patients.
Each sample was examined under the microscope and photographed in 20 randomly chosen places. On the basis of analysis of the pictures showing the area of 100 x 100&mgr;m, the selected cumulative parameters such as count, numerical density, field area and field perimeter were determined for each sample. Then the average value of the parameters was determined as well.
Characteristics of the retinal images of the eye optical systems with implanted intraocular lenses
Author(s):
Damian Siedlecki;
Marek Zając;
Jerzy Nowak
Show Abstract
Cataract, or opacity of crystalline lens in the human eye is one of the most frequent reasons of blindness nowadays. Removing the pathologically altered crystalline lens and replacing it with artificial implantable intraocular lens (IOL) is practically the only therapy in this illness. There exist a wide variety of artificial IOL types on the medical market, differing in their material and design (shape).
In this paper six exemplary models of IOL's made of PMMA, acrylic and silicone are considered. The retinal image quality is analyzed numerically on the basis of Liou-Brennan eye model with these IOL's inserted. Chromatic aberration as well as polychromatic Point Spread Function and Modulation Transfer Function are calculated as most adequate image quality measures.
The calculations made with ZemaxTM software show the importance of chromatic aberration correction.
Retinal images in the human eye with implanted intraocular lens
Author(s):
Marek Zając;
Damian Siedlecki;
Jerzy Nowak
Show Abstract
A typical proceeding in cataract is based on the removal of opaque crystalline lens and inserting in its place the artificial
intraocular lens (IOL). The quality of retinal image after such procedure depends, among others, on the parameters of the
IOL, so the design of the implanted lens is of great importance. An appropriate choice of the IOL material, especially in
relation to its biocompatibility, is often considered. However the parameter, which is often omitted during the IOL design is
its chromatic aberration. In particular lack of its adequacy to the chromatic aberration of a crystalline lens may cause
problems.
In order to fit better chromatic aberration of the eye with implanted IOL to that of the healthy eye we propose a hybrid - refractive-diffractive IOL. It can be designed in such way that the total longitudinal chromatic aberration of an eye with
implanted IOL equals the total longitudinal chromatic aberration of a healthy eye.
In this study we compare the retinal image quality calculated numerically on the basis of the well known Liou-Brennan
eye model with typical IOL implanted with that obtained if the IOL is done as hybrid (refractive-diffractive) design.
Influence of image doubling on modulation transfer function of optical systems
Author(s):
Radek Melich;
Zbynek Melich
Show Abstract
Prisms or prism systems in optical systems are used in different fields of science and engineering very frequently. Their technological deviations (e.g. degree of deviation between sides, etc.) induce an image doubling. In this paper we present a detailed analysis of the image doubling influence on the Modulation Transfer Function (MTF) of the optical system. Relations that enable to determine the acceptable technological tolerances of optical prism elements so that allowed image doubling does not create the unacceptable decrease of MTF of optical system under a test are derived.
Influence of small deformation of optical element surfaces on optical system imaging quality
Author(s):
Zbynek Melich;
Radek Melich
Show Abstract
In this paper, the influence of surface micro-deformations of optical elements on an imaging quality of optical systems is studied. The discussed optical elements are made up of metal, glass or plastic material which are manufactured by a point machining (a turning operation), optical elements that are moulded from glass or plastic material and optical elements that are manufactured by classical technology, etc. The surface micro-deformations of optical elements surfaces are sources of optical aberrations which can decrease an imaging quality. As an imaging quality criterion of optical systems it is considered Strehl definition which describes in adequate way optical systems loaded by small aberrations. A detailed theoretical analysis of the influence of micro-deformations basic types on a value of the Strehl definition is introduced. New relations for a determination of acceptable optical elements micro-deformations are derived.
Distorsion of ultrashort light pulses in optical systems
Author(s):
Antonin Miks;
Jiri Novak
Show Abstract
Ultrashort light pulses are distorted in optical systems due to a different magnitude of the phase and group velocity of the wave. Our work is focused on the analysis of the problem. The presented work provides a theoretical analysis of the influence of the imaging optical systems on the transformation of the light pulse that propagates through such systems. It is derived the theoretical formula for calculation of the change of wave aberration of the optical system in dependence on the frequency of light passing through the optical system. New relations are described that enable to calculate the complex wave field transformed by the optical system with aberration. These relations are valid even for the systems with a large numerical aperture and are not restricted to the paraxial or the third order aberration space.
Chromatic aberration coefficients
Author(s):
Antonin Miks;
Jiri Novak;
Pavel Novak
Show Abstract
Our work deals with the influence of the wavelength of light on values of wave aberration coefficients. It is proposed a technique for calculation of the dependence of aberration coefficients on the wavelength, their interpretation and the connection to chromatic aberrations. It is also shown the calculation of the Strehl definition using chromatic aberration coefficients and the tolerance limits are given. The proposed method for calculation of chromatic aberration coefficients is shown for the case of the imaging of axial point by the rotationally symmetrical optical system. Relations that enable calculation of chromatic aberration coefficients up to fifth order are carried out. These relations are accurate enough for most optical systems in practice.
Education kits for fiber optics, optoelectronics, and optical communications
Author(s):
Martin Hájek;
Miroslav Švrček
Show Abstract
Our company MIKROKOM, s.r.o. is engaged for many years in development of education equipment and kits for fiber optics, optoelectronics and optical communications. We would like to inform competitors of conference about results of this long-time development.
Requirements on education kits and equipment in a modern and dynamic area as is optical communications and fiber optics are quite difficult. The education kits should to clearly introduce students to given issue - the most important physical principles and technical approaches, but it should to introduce also to new and modern technologies, which are quickly changing and developing. On the other hand should be these tools and kits reasonable for the schools.
In our paper we would like to describe possible ways of development of this education kits and equipment and present our results of long-time work, which covers very wide range. On the one hand we developed equipment and kits for clear demonstration of physical effects using plastic optical fibers POF, next we prepare kits with a glass fibers, which are the most used fibers in practice and after as much as the kits, which covers broad range of passive and active elements of the optical networks and systems and which makes possible to create complex optical transmission connection. This kind of systems with using corresponding tools and equipment introduce the students to properties, manipulation, measurement and usage of optical fibers, traces and many active and passive components. Furthermore, with using different sorts of optical sources, photodetectors, fiber optics couplers etc., students can get acquainted with all optoelectronics transmission system, which uses different sorts of signals. Special part will be devoted also to effort mentioned before - to implement modern technologies such as e.g. Wavelength Division Multiplex (WDM) into the education kits.
Our presentation will inform auditors about development of mentioned education kits and equipment and about their potentials and practical utility at school education.
Coherent-state information concentration and purification in atomic memory
Author(s):
Jiří Herec;
Radim Filip
Show Abstract
We propose a feasible method of coherent-state information concentration and purification utilizing quantum
memory. The method allows us to optimally concentrate and purify information carried by many noisy copies
of an unknown coherent state (randomly distributed in time) to a single copy. Thus non-classical resources and
operations can be saved, if we compare information processing with many noisy copies and a single copy with
concentrated and purified information.
Some optical properties of metal in non-local potential theory
Author(s):
Janusz Chrzanowski
Show Abstract
On the grounds of the non-local potential we can obtain a modified Schrödinger equation which allows on simple turn to the transform domain. Thereby the total energy of electron understood in terms of quasiparticle becomes an explicit function of the wave number. In result the response of the metal surface to the external electromagnetic radiation one can analyze in more general way.
Human factor as an important phenomenon for the optical radar station operation
Author(s):
Antonin Novotny;
Josef Blazej
Show Abstract
Satellite laser ranging station close Helwan, a suburb of Egyptian capital city Cairo, is the cooperative lab of the astronomical department of National Research Institute of Astronomy and Geophysics, Egypt and the department of physical electronics of Czech Technical University, Faculty of Nuclear Sciences and Physical Engineering, Czech Republic. The aim of the station is the accurate and precise measurement of distance between station reference point and some artificial satellites. The measurement is based on an optical radar principle. The station location is determined by both attractive location from point of view geosciences and acceptable local climatic conditions. We are reporting about the involving local staff in the daily operation of the station and about influence of the training, motivation and local staff qualification improvement on measurement results.
Preparation of bismuth-doped yttrium iron garnets and their characterization
Author(s):
Jana Pigošová;
Anna Kiliánová;
Pavel Vojtek;
Michal Kopčok;
Alexander Cigáň
Show Abstract
This paper presents the study of bismuth-doped yttrium iron garnets with composition Y3-xBixFe5O12 (Bi: YIG) prepared by sintrating of metal oxides for various sintrating conditions (times, temperatures, etc.). The structure of the samples was characterized by XRD patterns. The spectra, obtained by LIB (Laser Induced Breakdown) method that is based on the interaction of high power laser beam with studied medium, are also presented. Breakdown and following ablation were induced on the sample surface in air by focusing mode-locked Nd: YAP laser radiation. The laser-induced spectra for various bismuth-donated samples and metal oxides are compared.
Vision screening in school children in Strzelin County
Author(s):
Marek Zając
Show Abstract
Investigation of children vision is one of the most important tasks in pediatric medical care. According to World Health Organization screening done with rapid and simple tests should be considered as initial step of such care. Thanks to simple screening tests it is possible to identify children who probably are burden with eye problems and to distinguish them from the children with correct vision.
Typical test for screening 6-years-old children (beginning their school education) includes, among others, evaluation of visual acuity for far and/or near and evaluation of binocular vision.
This contribution describes the methods and results of screening program covering 21 elementary schools and 450 children in Strzelin County (Lower Silesia). Visual acuity was measured with help of SCOLATESTTM and binocular vision with RANDOM DOT E STEREOTEST. Additionally color recognition was tested with Ishihara Children Plates. The results suggest that almost 29% of investigated children have refraction error (9% being myopes and 20% being hyperopes), and 9% has problems with binocular vision.