This PDF file contains the front matter associated with SPIE Proceedings Volume 9659, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

It is known today that crowdfunding is a very popular approach that simultaneously assists in rapidly disseminating creative ideas, performing worldwide market survey, getting the fund, and eventually starting the business. Hence, this article highlights some of the photonics-related ideas that are explored through the promising crowdfunding approach. These include microlenses for mobile devices, specially designed lenses for helmets and solar cells, three-dimensional optical scanners, optical spectrometers, and surface plasmon resonance-based optical sensors. Most of them looks simple and yet are very creative backing up with interesting stories behind them to persuade the target customers to participate.

It will be useful in biological applications if two or more physical parameters are simultaneously measured in a digital holographic microscope. In this paper, we present a hybrid digital holographic microscope that can measure simultaneously three-dimensional (3D) phase and 3D fluorescence distributions. This property has big advantage compared with conventional optical microscopes such as phase contrast microscope and fluorescence microscope. We present an optical setup for measuring both phase and fluorescence images. In the experiments, two objects that are fluorescence beads and egera densa are used. The separation method of phase and fluorescence images is presented.

An optical profilometer composed of an optical frequency comb source, a single pixel camera, and an optoelectronic interferometer in radio frequecny range have been developed toward large volume metrology. The optical profilometer allows us to measure an object with a large depth much more than a light wavelength without any 2π phase ambiguity. The wide dynamic range is achieved with high stability of the optical frequency comb and the simultaneous multi-singlefrequency operation. The single pixel camera is used for two-dimensional imaging without a mechanical scanning and the compressive sensing technique reduces the number of measurements. A surface profilometry for an object with a depth of several centimeters to a meter is demonstrated.

Combination of optical encoding and algorithmic decoding provides high-performance and high-functional imaging modalities known as computational imaging. Multi-aperture optics has been effectively utilized as an optical encoder and enables us to implement novel imaging methods and systems. In this paper, two instances of computational imaging using multi-aperture optics are presented with different types of apertures embedding in the optical system. A compound-eye imager is a flexible and versatile imaging system composed of multiple image fields, which was applied to intra-oral diagnostics. Single-shot phase imaging capable of capturing a large complex field is achieved by multi-aperture optics with a coded aperture. In both cases, the encoded signals are processed to retrieve desired information under the framework of computational imaging.

Single exposure phase-shifting digital holography is mandatory for recording/analyzing dynamic phenomena. As one of the candidate for the single exposure phase-shifting digital holography is the wave-splitting phase-shifting digital holography. We have proposed generalized phase-shifting digital holography as one of the wave-splitting phase-shifting digital holography. In the digital holography, the phase-shift quantity, which corresponds to the difference between the phase quantities of the reference wave on the adjacent pixels is generalized different from ordinal wave-splitting methods. Owing to the generalized phase-shifting, we can use a random-phase wave as the reference wave. The proposed phase-shifting digital holography enables us to record a fully-complex field of a dynamic phenomena without dc and conjugate terms using a commercially available optical devices. The relation between the property of the reference wave and the quality of the reconstructed images are discussed. Experimental results are given to confirm the proposed phase-shifting digital holography.

As a high-speed three-dimensional (3D) imaging technique, parallel phase-shifting digital holography is presented. This technique records a single hologram of an object with an image sensor having a phase-shift array device and reconstructs the instantaneous 3D image of the object with a computer. In this technique, a single hologram in which the multiple holograms required for phase-shifting digital holography are multiplexed by using space-division multiplexing technique pixel by pixel. Also, we present a high-speed parallel phase-shifting digital holography system. The system consists of an interferometer, a continuous-wave laser, and a high-speed polarization imaging camera. Motion pictures of dynamic phenomena at the rate of up to 1,000,000 frames per second have been achieved by the high-speed system.

At the beginning of this century, lighting technology has been shifted from discharge lamps, fluorescent lamps and electric bulbs to solid-state lighting. Current solid-state lighting is based on the light emitting diodes (LED) technology, but the laser lighting technology is developing rapidly, such as, laser cinema projectors, laser TVs, laser head-up displays, laser head mounted displays, and laser headlamps for motor vehicles. One of the main issues of laser displays is the reduction of speckle noise¹). For the monochromatic laser light, speckle is random interference pattern on the image plane (retina for human observer). For laser displays, RGB (red-green-blue) lasers form speckle patterns independently, which results in random distribution of chromaticity, called color speckle²).

Acousto-optic effects have been used to perform computationally extensive signal and image processing. The paper first discusses spatial modulation of light by using the acousto-optic modulator. Following this, applications of the acoustooptic modulator to time signal analysis are presented, with the emphasis on the Fourier spectrum analysis and joint timefrequency signal representation.

A Comparative study of step-index and trench-assisted single mode fiber in terms of bending losses and mode field diameter is carried out. Trench- index fiber proved to be a potential candidate for fiber-to-the-home application.

640 Gbit/s format conversion of RZ-OOK to NRZ-OOK has been numerically demonstrated with a specially-apodized linearly-chirped fiber Bragg grating in transmission. The spectral response of the Bragg grating is designed according to the optical spectra of the algebraic difference between RZ-OOK and NRZ-OOK signal.

The TOP detector at the Belle II Experiment is a particle identification detector, devoted mainly to the separation of charged pions and kaons. The charged particles emit Cherenkov photons when traversing a quartz radiator and these photons are converted inside micro-channel plates photomultipliers. The time of arrival and position of the photoelectrons, detected with excellent spatial and time resolution, are used to reconstruct the angle of the Cherenkov light emitted by the charged particle. The monitoring of the time stability and the measurement of the quantum efficiency of the photomultipliers are performed with a laser calibration system, with a target time resolution better than 50 ps. The system is a combination of a picosecond laser source, long single mode fibers, fiber bundles, and microlenses, which are needed to illuminate all the channels of the photomultipliers. A detailed description of the laser calibration system and its properties is given.

The systems to record incoherent holograms using a rotational shearing interferometer is demonstrated. The systems can record incoherent holograms by self-interference of the two coherent object points created by the beam splitter from one object point. In general, the rotational shearing interferometer cannot reproduce any depth information. The proposed rotational shearing interferometer has the advantage of obtaining depth information by the reconstruction owing to lenses for the shear which is parallel to the optical axis. A preliminary experiments were performed. The object images at some reconstruction distances were reconstructed numerically. The experimental results confirm the proposed system.

Properties of Wigner-Ville distribution’s coefficients obtained from in-line holograms are studied. It is found that the WVD coefficients corresponding to local fringe frequencies are mainly confined along a diagonal stripe intercepted at the origin of the WVD plane. The slope of this diagonal stripe is inversely proportional to the particle position. One of the coefficients always has minimum amplitude, regardless of the particle position.

Protoplast fusion is a physical phenomenon that two protoplasts come in contact and fuse together. Doing so, it is possible to combine specific genes from one protoplast to another during fusion such as drought resistance and disease resistance. There are a few possible methods to induce protoplast fusion, for example, electrofusion and chemical fusion. In this study, chemical fusion was performed with laser applied as an external force to enhance rate of fusion and observed under a microscope. Optical tweezers (1064 nm with 100X objective N.A. 1.3) and excimer laser (308 nm LMU-40X-UVB objective) were set with a Nikon Ti-U inverted microscope. Samples were prepared by soaking in hypertonic solution in order to induce cell plasmolysis. Elodea Canadensis and Allium cepa plasmolysed leaves were cut and observed under microscope. Concentration of solution was varied to induce difference turgor pressures on protoplasts pushing at cell wall. Free protoplasts in solution were trapped by optical tweezers to study the effect of Polyethylene glycol (PEG) solution. PEG was diluted by Ca⁺ solution during the process to induced protoplast cell contact and fusion. Possibility of protoplast fusion by excimer laser was investigated and found possible. Here we report a novel tool for plant cell fusion using excimer laser. Plant growth after cell fusion is currently conducted.

The red-shift on fluorescent dyes spectra at high concentration was investigated by laser induce fluorescence technique. In this research, the fluorescent dyes (Rhodamine 6G, Rhodamine B, Fluorescein and Bromofluorescein) were used. The sample solutions were prepared with methanol solvent in the concentration range of 10^-5 to 10^-3 Molar and the temperature of sample solution was controlled at 25 °C by temperature control chamber. Then, the sample solution was illuminated by violet laser (405 nm) excitation source and the fluorescence spectra were recorded by CCD spectrometer. The result showed that the fluorescence spectra of all fluorescent dye solutions were dependent on concentration of fluorescent dyes. The position of fluorescence maximum intensity was shifted to a higher wavelength (red-shift) when the concentration increased because the dimer formation rate increases with increasing concentration, but the shifting of wavelength for each fluorescent dye solutions was different, which suggests the different rate of formation of dimer molecules in each fluorescent dye solutions.

The interference of two photons in the optical gating Michelson interferometer is investigated. The phenomenon is studied using two different representations of photons: the space-time domain and a step-by-step two photon state evolution. Both representations lead to an equivalent description of the two-photon states which is the interference of four cases of two-photon traveling states, as implied by the evolution analysis. Additionally, the space-time domain analysis reveals that the classical interference of high-intensity light source is identical to the two-photon interference in the quantum regime except for a multiplicative factor of (ⁿ ₂), where n is the number of photons.

The phase shift on reflection from the colloidal photonic crystal film was measured by the Fabry-Pérot resonant cavity along the cross-section of the photonic crystal film without additional optical parts. The wet colloidal photonic crystal film was fabricated by dip-coating an agarose-gel-coated glass substrate into a suspension containing monodisperse polystyrene nanospheres with the diameter about 188 nm. The ordered structure of monodisperse spheres in the wet film on hydrogel contributed the reflection stopband of photonic crystals together with Fabry-Pérot interference fringes of this uniform wet film over the entire visible region. The spectrum of reflectance was observed under the reflected microscope with the optical fiber spectrometer. The analyzed experimental results show the thickness of film about 20 μm and the photonic stopband peak at ~470 nm. The variation of phase shift values between both edges of the peak varies from 0.07π to 0.88π which is in range of 0 to π as reported by other works. Moreover, these extracted optical properties are slightly changed due to the gradual water evaporation of the wet film. This stopband peak of photonic crystal is shifted to a shorter wavelength due to the more packing of nanospheres after drying.

Numerical results using transfer matrix method (TMM) of omnidirectional photonic band gap (omni-PBG) for both TE and TM polarizations from 0º to 89º for THz responses are presented. Such omni-PBG design is based on one-dimensional photonic crystal (1D-PC) containing thin slices of 10 pairs of high-resistivity silicon and magnesium fluoride (MgF₂) as the high and low refractive index components respectively, in the (HL)¹⁰ structure. With a quarter-wavelength thickness of layer, the thickness increase of either high or low index layer increases this PBG redshift for TE as well as TM polarizations. Conversely, decreasing the thickness causes the PBG of both TE and TM polarizations to become blueshift. This also gives rise to the spectral shift for the omni-PBG. High reflectivity omni-PBG within a certain wavelength is found in the range of 390-515 μm. This suggests a practical way of controlling the thickness of layer to achieve a suitable omni-PBG. This structural design shows the potential of omnidirectional mirror as a key element in THz communication system. In addition, the proposed structure shows a probable application based on the polarization sensitivity of the structure. At an angle of incidence greater than 60º, the TM polarized mode is highly transmitted whereas the transmittance of the TE polarized mode become nearly zero. The TM mode filter is therefore realized.

The optical fiber filter can be used to reject the noise or unwanted spectrum in the optical communication system. In this study, the performance of the optical fiber filter in visible and near-infrared wavelengths is studied. The working principle of the filter is based on the cladding mode coupling to the high order mode introduced by perturbation on a short section of single-mode (SM) fiber with a specific cut-off wavelength. In the previous study, the filtered wavelengths from the SM-fibers with the cut-off wavelength of 600 nm are 547 nm and near IR range (980-1,100 nm). The filtered wavelength from the SM-fiber with the cut-off wavelength of 800 nm is 666 nm. Also, the magnitude of the filtered wavelengths can be controlled by the magnitude of the applied perturbation force. In this study, the green solid state laser with the wavelength of 532 nm (2^nd harmonic component), 808 nm (pump wavelength), and 1,064 nm (fundamental component) and the red diode laser with the wavelength of 668 nm are launched into the SM-fiber with the cut-off wavelength of 600 and 800 nm, respectively. The experimental results clearly show that the harmonic wavelength of 1,064 nm of green laser can be filtered out by the fiber with cut-off wavelength of 600 nm up to 66% with the perturbation force 60 N. The fiber with cut-off wavelength of 800 nm can reject the red laser spectrum up to 50% with the perturbation force 80 N.

This paper presents the polarizing triangular cyclic interferometer (pTCi) for characterizing optical samples with birefringent properties such as half- and quarter-wave plates. The interferometric system was set up to analyze the phase retardation of wave retarders in both qualitative and quantitative aspects. For the qualitative aspect, the distinct signal outputs from the inspected birefringent components oriented at particular angles are employed to distinguish different types of optical devices. For the quantitative aspect, the same arrangement could determine the phase difference γ of unknown retarders, so that it could be used to characterize types of samples. The experimental results showed the corresponding results obtained from both mentioned aspects where γ were measured to be 89.62° and 177.17° for half- and quarter-wave plates, respectively. The pTCi has been proved to be a proper scheme to characterize optical samples with birefringent properties.

Extensive research on interpreting the clinical signs of corneal-arcus formation and their related diagnostics potentials have found that there is a strong correlation of the arcus formation with the risk of coronary artery diseases and lipid stratification. Clinically the stages of the arcus formation are normally observed as separate grey-whitish arcs, that are formed at the inferior and then at the superior poles of the cornea. These arcs will by time being elongated to form a ring approximately 1 mm in width. In this paper, efforts to develop quantification system that is capable to recognize the stages of the arcus formation will be reported. The quantification was based on eye-images taken using prior developed low-cost digital image acquisition system, which self constructed from a plastic safety welding-goggle that was modified by placing two Logitec C525 webcam and LEDs lighting system. Pattern images of arcs with variation of arc's positions, lengths and thickness were used for pre-calibration purposes. Then these similar arcs are drawn on the of periphery of cornea images to simulate dummy corneal arcus, which mimick the stages of corneal arcus development. Using 672 data images, results of recognition show a good recognition rate, i.e. 93.6 % for determining arc's length (with maximum %RSD of 5.67 %) and 84.83 % for determining arc's thickness (with maximum %RSD of 5.67 %). Worser precision data were observed to happen for the small arc's length as well as small arc's thickness. Current efforts are devoted to translate the system for clinical trials.

Photostress analysis system was used to study the stress distribution on a circular disk. A reflection polariscope was used to observe the surface strains from the recorded fringe patterns by digital camera. The shape of sample is a circular disk was pressed on the top and bottom and the polariscope produced fringe patterns from sample on the model being stressed. The results were analyzed, the fringe pattern looked different in various magnitude of force because the stress distribution in sample was changed with magnitude of force. Deformation can be determined from the fringe patterns.

A farmer usually uses a cheap chemical material called chlorine to destroy the cell structure of unwanted organisms and remove some plant effluents in a baby shrimp farm. A color changing of the reaction between chlorine and chemical indicator is used to monitor the residue chlorine in water before releasing a baby shrimp into a pond. To get rid of the error in color reading, our previous works showed how a smartphone can be functioned as a color reader for estimating the chlorine concentration in water. In this paper, we show the improvement of interior configuration of our prototype and the distribution to several baby shrimp farms. In the future, we plan to make it available worldwide through the online market as well as to develop more application programs for monitoring other chemical substances.

Based on our research work in the last five years, this paper highlights our innovative optical sensing system that can identify and separate silkworm gender highly suitable for sericulture industry. The key idea relies on our proposed optical penetration concepts and once combined with simple image processing operations leads to high accuracy in identifying of silkworm gender. Inside the system, there are electronic and mechanical parts that assist in controlling the overall system operation, processing the optical signal, and separating the female from male silkworm pupae. With current system performance, we achieve a very highly accurate more than 95% in identifying gender of silkworm pupae with an average system operational speed of 30 silkworm pupae/minute. Three of our systems are already in operation at Thailand’s Queen Sirikit Sericulture Centers.

We present a method to obtain a set of spectral component of three-dimensional images based on measurements of hyperbolic volume interferogram. The method uses an improved two-wavefront folding interferometer incorporating with a single detector of high sensitivity. The method may apply to usual polychromatic objects because it is kind of incoherent holography combined with Fourier transform spectroscopy. First experimental result of the method is shown to demonstrate the capability to acquire continues spectral profile of three-dimensional polychromatic object.

A four-dimensional impulse response function for the digital holographic three-dimensional imaging spectrometry has been fully derived in closed form. Due to its factorizing nature of the mathematical expression of four-dimensional impulse response function, three-dimensional spatial part of impulse response function directly corresponds to threedimensional point spread function of in-line digital holography with rectangular aperture. Based on these mathematical results, this paper focuses on the investigation of spectral resolution and three-dimensional spatial resolution in digital holographic three-dimensional imaging spectrometry and digital holography. We found that the theoretical prediction agree well with the experimental results. This work suggests a new criterion and estimate method regarding threedimensional spatial resolution of in-line digital holography.

A transversely excited atmospheric pressure nitrogen laser (TEA N₂ Laser) is a molecular pulse gas laser, operated at atmospheric pressure, which generates an electromagnetic wave in ultraviolet wavelength of 337.1 nm. It can operate without an optical resonator. We present a TEA N₂ laser setup excited by an electronic discharge circuit known as the Blumlein circuit. Our setup is composed of simple components commonly found in everyday life. The setup can be utilized in classroom to demonstrate the dependence of the laser intensity on the flow rate of nitrogen gas.

In this contribution, a technical development of the laser scattering measurement for laser removal of graffiti is reported. This study concentrates on the removal of graffiti from metal surfaces. Four colored graffiti paints were applied to stainless steel samples. Cleaning efficiency was evaluated by the laser scattering system. In this study, an angular laser removal of graffiti was attempted to examine the removal process under practical conditions. A Q-switched Nd:YAG laser operating at 1.06 microns with the repetition rate of 1 Hz was used to remove graffiti from stainless steel samples. The laser fluence was investigated from 0.1 J/cm² to 7 J/cm². The laser parameters to achieve the removal effectiveness were determined by using the laser scattering system. This study strongly leads to further development of the potential online surface inspection for the removal of graffiti.

In recent years, oil spills have become a significant environmental problem in Thailand. This paper presents a laser treatment for controlled-clean up oil spill from coastal rocks. The cleaning of various types of coastal rocks polluted by the spill was investigated by using a quasi CW diode laser operating at 808 nm. The laser power was attempted from 1 W to 70 W. The result is shown to lead to the laser removal of oil spill, without damaging the underlying rocks. In addition, the cleaning efficiency is evaluated using an optical microscope. This study shows that the laser technology would provide an attractive alternative to current cleaning methods to remove oil spill from coastal rocks.

Here, we demonstrate the combined influence of Intrapulse Raman Scattering (IRS), Self-Steepening (SS) and negative Third Order Dispersion (n-TOD) on soliton interaction. The peculiar particle nature of soliton results in interaction of in-phase adjacent pulses while helps in deviation of out-of phase pulses. We show how the interaction of the soliton can be avoided due to combined effect of IRS, SS and negative TOD as these effects apart from various nonlinear dynamics results in shifting of pulses. The interaction point of solitons in 160 Gbps system is found to be at 24.22Km for an initial relative spacing of q_o=5.28 using Perturbation theory. This in-phase soliton pair tracing inside the fiber in noted using Split-Step Fourier Transform. Further, impact of interaction is realized in 160 Gbps telecommunication model which yielded Q=0 at I_p depicting perfect interaction resulting in bit error without influence while yielded fair Quality facto of 112.375, 124.59, 93.57, 75.12, 63.23 and 46.97 with influence for various TOD values of -0.03, -0.04, -0.05, -0.06, -0.07 and -0.09 ps³/Km and T_R=4fs demonstrating no interaction.

The Arc Discharge Drawing (ADD) technique offers a promising alternative for fabricating silica nanowires. In the previous study, ADD technique was based on the creation of a high voltage glow discharge between two electrodes. Such a configuration provides the heat zone that occurs perpendicularly to the fiber. With ADD technique, silica wires with diameters as small as 50 nm were achieved. Despite these successes the further development is meant to be continued. In this paper, ADD technique is improved by adding a pair of electrodes. The arc discharge apparatus consisting of four electrodes is proposed. The arranged two pairs of electrodes offer the sandwich-heat source configuration. The computer-controlled stage allows the drawing speeds in the range of 12 mm/s to 25 mm/s. The nanowires can be produced by varying the voltage in the range of 4 kV to 5 kV. The optimum operational voltage is investigated by the scanning electron microscope (SEM) images of the fabricated nanowires. This result strongly suggests further improvements in glass fiber drawing technology to produce nanowires.

We report a simple method to synthesize Zinc oxide nanorods, grown without using catalysis with less complicity. This was done by hydrothermal treatment of zinc nitrate and hexamine at 90°C and various times (5- 20h) and also we find that the nanorod size and shape depends on heating rate, temperature and heating time. ZnO nanorods have been investigated for their light guiding ability and their effective index of refraction for use in near air index optical systems by developing a ridge waveguide structure. ZnO nanorod waveguides (100 μm w x 2.5 μm h x 1mm l) were grown on a seeded glass substrate template using hydrothermal process at 90°C. Modification of the substrate surface in order to obtain dense perpendicularly-oriented ordered nanorods induced selective growth. These structures were characterized by SEM, EDX, and XRD. The guiding property, i.e. locally excited photoluminescence propagation along the length of the waveguide, was analyzed with imageprocessing program in MATLAB. Following application of a fiber optic white light source on the ZnO nanostructure, we found that light propagation occurred within the glass substrate. No such propagation occurred if light was applied on uncoated areas of the glass. Modeling of waveguide behavior to determine the number propagating modes was exercised using waveguide mode solver in COMSOL.

This paper deals with mathematical modeling and study of nonlinear switching in optical fiber Bragg gratings (FBG) by a transfer matrix method. Critical parameters contributing to high performance nonlinear fiber Bragg grating were studied. The transmission spectrum centered at 1550 nm was analyzed with varying number of layers and refractiveindices. The study showed that by proper modification in grating length of the FBG, we were able to optimize transmission spectrum for required application. The nonlinear behavior of FBGs can be further applied in optical switching applications (all-optical logic gates).

In this paper, we discuss the digital holography (DH) experiment in our optical and communication laboratory course for undergraduate students at Physics department, KMITL. The purposes of DH experiment are presenting our students the meaning and advantage of DH and its applications. The Gabor configurations of in-line DH has been set up for recording a number of samples, which were placed on different distances, simultaneously. Then, the images of all objects have been numerical reconstructed by using computer. The students have been learned that all of reconstructed images have been got from only one time recording, while using the conventional recording technique, sharp images of different objects have been gotten from different recording time. The students also have been learned how to use DH technique for investigation some different kinds of samples on their own of interested such as a human hair or a fingerprint. In our future work, our DH system will be developed to be a portable apparatus for easily showing to children in different areas.

Converting infrared radiation in the form of heat into electricity is one of the interesting energy conversion approaches. This can be simply accomplished through thermoelectric effect with the well-known device called thermoelectric cooler (TEC). In this paper, we briefly overview TEC-based concepts, demonstrations, and products for converting heat into electricity. We then propose our own portable TEC-based heat-to-electricity converting module. Experimental proof of concept is also highlighted showing a promising output voltage of 5VDC and 0.224A suitable for low voltage applications. Future work relates to design optimization, engineering improvement, and testing in real world scenario.

In this research, two-wave coupling in photorefractive lithium niobate crystal has been used to do imaging enhancement of digital holography (DH) system. The image bearing beam of in-line DH system has been incident and interfered with a reference beam that was emerged from the same laser on a LiNbO₃ crystal. With certain angles between both beams, the energy of the reference beam was transferred to the image bearing beam then resulted the enhancement of the reconstructed image of the DH system. By using the suitable intensity of laser beam with a right PR crystal, the image from an in-line DH imaging system would be improved.

In this paper we propose a modern technique to evaluate the shape changes of solder paste by using double-view in-line digital holography. We observed the transformation of three different kinds of solder paste composition: pure solder paste, solder paste mixed with 0.02%, 0.05%, 0.10% graphene (GPN) and 0.02%, 0.05%, 0.10% graphene oxide (GPNO), respectively. The shape of the solder pastes was investigated at different melt temperatures (i.e. 200°C, 250°C, and 300°C) for 30 seconds using a collimated beam propagating through the solder paste, then being double reflected on a mirror and second incident on another sides of the solder paste. The double images bearing beams were recorded with a CCD sensor simultaneously. The single recorded digital hologram from double view technique was reconstructed using digital holography. The results show that the double-view technique provides reliably data. Moreover, it would be developed for observing more than two images by single holography writing in the future.

Knowledge of optical fibers and fiber devices ageing is one of necessary conditions for successful applications of fiber communication systems into hard environmental surrounding and for application of fiber sensors. This paper deals with finding of typical ageing markers during the process of accelerated ageing. Basic fiber parameters as the attenuation, NA, Brillouin frequencies have been measured under higher temperature and fiber attenuation has been measured for gamma loading.

Detection of a subspace anomaly is an important application of hyperspectral imaging in remote sensing. Sub-space anomaly detection depends on the unknown dimension of the main background subspace. When the dimension is high, detection algorithms tend to have unsatisfactory performance. This paper proposes an anomaly detection algorithm that will continue to perform satisfactorily when the dimension is high.

Measurement of certain types of spatial coherence functions allows us to obtain three-dimensional (3-D) images of many spectral components for usual objects under illumination of white light. We have developed some of these techniques, which are regarded as combination of incoherent holography and Fourier transform spectroscopy. We illustrate the principle of the basic technique, and then report on advances in alternative techniques. Recent experimental and theoretical achievements are shown to demonstrate the performance of the techniques.

Temperature tuning of lasing emission from dye-doped cholesteric liquid crystal (CLC) at intermediate twisted phase has been demonstrated in this work. With heavily doping of 42.5% chiral molecules into the nematic liquid crystals, the shifts of photonic bandgap versus temperature is obviously as thermal controlling of the sample below the certain value. By the differential scanning calorimetr measuremet, we demonstrate the phase transition from the CLC to the smectic phase when the temperature is lowered to be about 15°C. Between CLC and smectic phase, the liquid crystal mixtures are operated at intermediate twisted phase that can be used the temperature related refractive mirror. After pump by the Q-switched Nd:YAG laser, the lasing emission from this dye doped LC mixtures has been demonstrated whose emission wavelength can be tuned from 566 to 637 nm with 1.4°C variation.

AlxGa1-xN photocathode was prepared by MOCVD and the reflectivity, transmittance, and absorptivity were test. Based on thin film principle, optical model of t-mode AlxGa1-xN photocathodes was built, and then optical properties and quantum efficiencies were simulated. Results show that AlxGa1-xN photocathodes satisfy the need of detectors with “solar blind” property when the Al component is larger than 0.250. There is an optimal thickness of AlxGa1-xN layer to obtain highest quantum efficiency, and the optimal thickness is 0.3μm. There is close relation between absorptivity and quantum efficiency, which is in good agreement with the “three-step” model. This work gives a reference for the design and preparation of AlxGa_1-xN photocathodes.

We demonstrate side pumped ultra-compact Q-switched Er:glass laser for rangefinding with 1.4 mJ energy at 1.54 um. Laser diode with 75 W power and 5 ms pulse duration was used. Active medium was enveloped with diffuse reflector. Output pulse energy in free-running mode was 27 mJ with a slope efficiency of 12%. Transparent glass-ceramics containing Co2+:MgAl2O4 nanocrystals were used as a passive gate to ensure Q-switching in an operation temperature range and transverse mode selection. The Q-switch mode had steady operation at 1 Hz repetition rate with thermal effects playing no visible role.

We demonstrated three-dimensional position measurements of a gold nanoparticle using an in-line low-coherence digital holographic microscope with twilight-field method (TFM) and a regulation of temporal coherence of light source. An intensity of scattering light from a nanoparticle is very weak, and therefore, in order to get interference fringes with higher contrast, the TFM regulates only an intensity of the reference light to be close to an intensity of the object light using a low-frequency attenuation filter in the in-line digital holographic microscope. Coherence of light relates to get interference fringes with higher contrast on a wide aria. High coherence makes a lot of undesired coherent noises, therefore the fringes derived from nanoparticles is masked by them. Too low coherence makes fringes with low contrast and corresponding low signal-to-noise ratio. Consequently an adequate regulation of the coherence of light source gives the best performance in the position measurements. Uses of these methods allowed us to reach the minimum diameter of 20 nm in the position measurement of a gold nanoparticle.

Most of gem materials can be characterized by infrared absorption spectroscopy. Normally, mid infrared absorption technique has been applied for investigating fundamental vibrational modes. However, for some gem materials, such as tourmaline, NIR is a better choice due to differentiation. Most commercial NIR spectrometers employ complicated dispersive grating or Fourier transform techniques. In this work, we developed a filter type NIR spectrometer with the availability of high efficiency and low-cost narrow bandpass NIR interference filters to be taught in a physics laboratory. The instrument was designed for transmission-mode configuration. A 50W halogen lamp was used as NIR source. There were fourteen NIR filters mounted on a rotatory wheel for wavelength selection ranging from 1000-1650 nm with steps of 50 nm. A 1.0 mm diameter of InGaAs photodiode was used as the detector for the spectrometer. Hence, transparent gem materials can be used as samples for experiment. Student can learn vibrational absorption spectroscopy as well as Beer-Lambert law from the development of this instrument.

We measure the transient photocurrent of APFO3:PCBM bulk heterojunction solar cells illuminated with ns-laser and sub-ms LED light sources. The ratio of the number of collective charges to the number of excited photon (external quantum efficiency, EQE) and the transient photocurrent fall times have been carried out with difference pulse durations and fluences. The EQEs characterized by ns-laser source are shown to obey the bimolecular recombination at high excitation fluences. The increasing of transient photocurrent fall times suggests that the fall times of free charge carriers are effected by deep trap density of state (DoS) and thus the free charge carriers have a sufficient time for bimolecular recombination at short circuit condition. At the same fluences, however, the EQEs characterized by sub-ms LED sources exhibit an excitation fluences independence of EQE. The transient photocurrent fall times with sub-ms LED sources are rather constant when the excitation fluences increases indicating that the deep trap DoS has less effect at short circuit condition for longer pulse duration.

Carbon nanotubes (CNTs) were grown on Ni catalyst with Al catalyst supported layer prepared on silicon substrate at different temperatures by TCVD. TEM images clearly showed the multi-wall structure of carbon nanotubes (MWCNTs) and SEM images revealed that the average diameters of MWCNTs were 116, 121, 142 and 162 nm for the growing temperatures of 600, 700, 800 and 900°C, respectively. The increase of tube diameter was due to the difference of Ni particle size and distribution after pretreatment. Raman spectrum revealed the two peaks of the D and G band at 1282- 1290 and 1588-1598 cm^-1, respectively. The tubes grown at 800°C showed a shoulder peak of G band at 1598 cm^-1. The minimum of defect induced disorder (ID/IG) of 1.19 was found at 800°C whereas the maximum disorder of 1.70 was observed at 600°C. All results confirm that the tube growth at 800°C shows the minimum imperfective disorder and the tube diameter can be manipulated by the Ni particle size and distribution.

We demonstrate a durable and efficient 3 mJ 10 ns 100 Hz Nd:YAG laser developed with a view to the space borne operation. We discuss the cavity construction design principle, the approach to high efficiency and the smooth pulse operation. The experimental investigation for the best pair of Q-switch transmission and output coupler reflection coefficient is considered. The factors influencing the pulse shape are analyzed. The 100 Hz operation with good beam quality is demonstrated.

The effects of using copper sulfide (CuS) counter electrodes on the performances of solar cells made with CdS/CdSe/ZnS quantum dots co-sensitized onto hierarchical TiO2 spheres (HTS) used as photoelectrode is reported. The HTS in the QDSSCs is composed of an assembly of numerous TiO₂ spheres made by the solvolthermal method. The photoelectrical performance of HTS/CdS/CdSe/ZnS coupled to CuS counter electrode was compared to those coupled to Pt CE. The HTS/CdS/CdSe/ZnS coupled to the CuS CE showed the highest power conversion efficiency η (of 1.310 %.) which is significantly higher than those using a standard Pt CE (η = 0.374%) (3.50 fold). This higher efficiency is the results of the higher electrocatalytic activities when the copper sulfide CEs is used.

In this research, the nonlinear frequency conversion effect based on four-wave mixing (FWM) principle in a onedimensional graphene-based photonics crystal (1D-GPC) has been investigated numerically. The 1D-GPC structure is composed of two periodically alternating material layers, which are graphene-silicon dioxide bilayer system and silicon membrane. Since, the third-order nonlinear susceptibility χ⁽³⁾ of bilayer system is hundred time higher than pure silicon dioxide layer, so the enhancement of FWM response can be achieved inside the structure with optimizing photon energy being much higher than a chemical potential level (μ) of graphene sheet. In addition, the conversion efficiencies of 1DGPC structure are compared with chalcogenide based photonic structure for showing that 1D-GPC structure can enhance nonlinear effect by a factor of 100 above the chalcogenide based structure with the same structure length.

We studied photoemission of monosaccharides and disaccharides using laser-induced fluorescence spectroscopy. A 532- nm, 10 mW, laser was used to excite the samples and back-scattering signals were collected by a spectrometer. We found that most sugars show weak fluorescence in solid phase but do not fluoresce when dissolved in water solutions. The emission spectra show similar peak intensity at 590 nm, but they are different in emission intensities. We suggest that the fluorescence spectra may be used to differentiate sugar type, even though the origin of the fluorescence is unclear and needed further study.

Nowadays, metallic cables are produced so as to avoid the maximum allowable temperature of the cable by the normal operation and the maximum allowable temperature for short-circuit the exceeding the maximum allowable internal temperature. The temperature increase is an unwanted phenomena causing losses in the cable and its abrasion. Longterm overload can lead to damaging of the cable or to the risk of fire in extreme cases. In our work, we present the temperature distribution measurement inside the metallic cables using distributed temperature system. Within the cooperation with manufacturer of the metallic cables, optical fibers were implemented into these cables. The cables are double coated and the fibers are allocated between these coatings and also in the centre of the cable. Thus we are able to measure the temperature inside the cable and also on the surface temperature along the whole cable length with spatial resolution 1 m during the cable heating. This measurement method can be also used for short-circuit prediction and detection, because this phenomena is always accompanied with temperature increase. Distributed temperature systems are already successfully implemented in temperature measurements in industry environment, such as construction, sewer systems, caliducts etc. The main advantage of these systems is electromagnetic resistance, low application price and the possibility of monitoring several kilometers long distances.

We present results of numerical simulations of a supercontinuum generation (SCG) in a Ge_11:5As₂₄Se_64:5 chalcogenide rectangular waveguide with air as an upper cladding and the lower cladding is magnesium fluoride. A broadband infrared 1.3-3.0 μm SCG could be achieved by pumping with femtosecond pulses in the two zero dispersion wavelengths. The effect of chirp on SCG spectrum has been also investigated. The simulation shows a significant SCG spectral flatness in the mid-infrared range with positive frequency chirp input pulses.

The monitoring of building structures deformations and testing of construction materials resilience are very important processes in the development and production of given materials and structures. Undesirable or excessive deformations of materials are phenomena which are unacceptable in construction, especially in supporting structures. These issues are currently monitored by electromechanical sensor in most cases. It is a classic technique when the sensor measures the material stress at the point of its installation. This paper deals with the concrete deflection measurement using fiber optic distributed strain system. This system uses optical fiere as a sensor and operates at the principle of measurement of Brillouin frequencies. The mechanical stress on the optical fiber causes shift of these frequencies. This change is subsequently converted to stress unit micro-strain. In our experiments, the optical fiber was embedded in concrete along its whole length. The advantage of this system is that the measurement is carrying out along the entire fiber length with spatial resolution around 50 cm, so it is possible continuously measure several thousands of points at the distance of several kilometers.

This article is dealing with evaluation of air turbulences in uence on the laser beam in the simulation box with regards to change of beam polarization state. For measurement the laser optical source LDM1550 operating at 1550 nm and polarimeter PAX5710 were used. The laser source was placed in front of simulation box that served for generation of stable turbulent environment. The simulation of turbulent environment was generated by high-speed ventilators PMD1212PMB1-A. The thermal turbulences were created by Empire CTH-5000 and Solac TH 8325 heaters. All heaters were placed along the side of simulation box. With the help of polarimeter and detector PAN5710IR3 were then subsequently recorded changes of polarization state of the optical beam with regards to changes of turbulence condition within the box. The results are then discussed and interpreted with the help of statistic methods in the end of the article.

We present the parametric investigation of the axial trapping forces generated by the interaction of an ellipsoidal dielectric and a focused, randomly polarized Gaussian beam in the geometrical optics regime. We show that particle elongation along the optical axis results to a more unstable axial trap compared to that of a reference sphere due to the more positive axial forces for positive axial displacements. Decreasing the refractive index difference between the particle and the surrounding medium (Δn = 0.09) decreases the magnitude of the axial force for positive particle displacements; and for a narrow range of axial displacements an axial trap can be achieved. Increasing the beam wavelength increases the magnitude of the axial force and for 1060 nm an axial trap can be achieved.

The optical bistability is a fundamental nonlinear feature of the ring resonator. A geometric and potential dynamics interpretation of the bistability is given. Accordingly, the bistability of the nonlinear system is shown to be a consequence of geometric laws of vector calculus describing the resonator ring. In contrast, the so-called transcendental relations that have been obtained in the literature in order to describe the optical wave are interpreted in terms of potential dynamical systems. The proposed novel interpretation provides new insights into the nature of the ring resonator optical bistability. The fundamental work by Rukhlenko, Premaratne and Agrawal (2010) as well as a more recent study by Chiangga, Pitakwongsaporn, Frank and Yupapin (2013) are considered.

This article is dealing with an optical fiber refractive index design optimized for utilization in DTS (Distributed Temperature Sensing) measurements. Presented optical fiber uses wavelength of 850 nm for communication purposes and 1060 nm for sensory operation. The aim of this work is to design an optical fiber with redistribution of the optical field at 850 nm similar to communication multi-mode optical fiber 50/125 μm and for wavelength of 1060 nm the redistribution of the optical field will be shifted closer to the core-cladding boundary to increase its sensitivity to temperature. Optical properties obtained from fiber design are compared with standard multi-mode optical fiber with graded refractive index to ensure that new optical fiber design has better sensing characteristics, but still keeps good enough communication properties at the same time.

This paper discusses the implementation of a light emitting diode based visible light communication system for optical vehicle-to-vehicle (V2V) communications in road safety applications. The widespread use of LEDs as light sources has reached into automotive fields. For example, LEDs are used for taillights, daytime running lights, brake lights, headlights, and traffic signals. Future in the optical vehicle-to-vehicle (V2V) communications will be based on an optical wireless communication technology that using LED transmitter and a camera receiver (OCI; optical communication image sensor). Utilization of optical V2V communication systems in automotive industry naturally brings a lot of problems. Among them belongs necessity of circuit implementation into the current concepts of electronic LED lights control that allows LED modulation. These circuits are quite complicated especially in case of luxury cars. Other problem is correct design of modulation circuits so that final vehicle lightning using optical vehicle-to-vehicle (V2V) communication meets standard requirements on Photometric Quantities and Beam Homogeneity. Authors of this article performed research on optical vehicle-to-vehicle (V2V) communication possibilities of headlight (Jaguar) and taillight (Skoda) in terms of modulation circuits (M-PSK, M-QAM) implementation into the lamp concepts and final fulfilment of mandatory standards on Photometric Quantities and Beam Homogeneity.