Proceedings Volume 7057

The Nature of Light: Light in Nature II

cover
Proceedings Volume 7057

The Nature of Light: Light in Nature II

View the digital version of this volume at SPIE Digital Libarary.

Volume Details

Date Published: 10 August 2008
Contents: 4 Sessions, 13 Papers, 0 Presentations
Conference: Optical Engineering + Applications 2008
Volume Number: 7057

Table of Contents

icon_mobile_dropdown

Table of Contents

All links to SPIE Proceedings will open in the SPIE Digital Library. external link icon
View Session icon_mobile_dropdown
  • Front Matter: Volume 7057
  • Fundamental Properties of Light
  • Light and Biological Systems
  • Poster Session
Front Matter: Volume 7057
icon_mobile_dropdown
Front Matter: Volume 7057
This PDF file contains the front matter associated with SPIE Proceedings Volume 7057, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.
Fundamental Properties of Light
icon_mobile_dropdown
Gaussian-like shaping of coherent synchrotron x-rays: 3D diffraction at a 90-degree Bragg reflection
Andrei Y. Nikulin, Alexei Y. Souvorov
Gaussian-like shaping of the forward-diffracted intensity was observed from an initially rectangular cross-section of coherent x-rays. The effect occurs when a wavelength inside a crystal exactly matches the period of atomic net planes lying perpendicular to the incident beam. The transmitted peak intensity rose when the lateral width of the rectangular-shaped incident beam increased. The transmitted intensity profile spatially was significantly narrower than that of the incident beam size. The observations showed that, unlike in all other x-ray diffraction experiments, coherent and incoherent x-rays produced different dependences of the peak intensity and its width on the incident beam size.
Singular optical phenomena in nature
Optical singularities serve as scientific landmarks in the topological landscape of light patterns. These curious features exhibit conservation properties and unique diffraction patterns that are finding increasing importance in many branches of modern optics. Caustics are singularities in ray optics that are markedly different from those in wave optics owing to the inclusion of phase and polarization in the latter case. Optical vortices and polarization singularities are examples of singular patterns in electromagnetic fields. There is some evidence that single photons can also exhibit singular attributes. This talk will describe examples of both naturally occurring and man-made optical singularities, how they may be put to use, and future directions in this field.
Experimental investigation of the singular phenomena in statistical optical fields
This paper is a review and extension of our recent work on three types of singular optical phenomena in statistical optical fields, including phase singularities (optical vortices) in laser speckle fields, polarization singularities in polarization speckle, and coherence vortices in optical coherence functions. For the generation and detection of these unique singular optical phenomena, different optical setups have been introduced. Some geometric structures and statistics associated with singularities are also investigated by experiments.
Light and Biological Systems
icon_mobile_dropdown
Product piracy from nature: biomimetic microstructures and interfaces for high-performance optics
Robert Brunner, Arnaud Deparnay, Michael Helgert, et al.
Micro and nanostructured optical components are evolved over millions of years in nature and show a wide application range as microlens arrays, diffractive or subwavelength structures in manifold biological systems. In this contribution we discuss the advantages and challenges to transfer the concepts based on the nature models to increase the performance of high-end optical systems in applications such as beam shaping and imaging. Especially we discuss the application of sophisticated statistical microlens arrays and diffractive structures in different fields such as lithography, inspection or for medical instruments. Additionally we focus on anti-reflection coatings which are commonly used to suppress reflection of light from the surface of optical components in the visible range. We report an innovative approach for the fast and cost-efficient fabrication of highly UV transmissive, anti-reflective optical interfaces based on self assembled gold nanoparticles.
Photonic nanoarchitectures occurring in butterfly scales as selective gas/vapor sensors
L. P. Biró, K. Kertész, Z. Vértesy, et al.
Photonic band gap material type nanoarchitectures occurring in the wing scales of butterflies possessing structural color were investigated as selective gas/vapor sensors. From 20 examined butterfly species all showed selective sensing when various volatile organic compounds were introduced as additives in ambient air. Four butterflies species: Chrysiridia ripheus (Geometridae), Pseudolycena marsyas, Cyanophrys remus (both Lycaenidae) and Morpho aega (Nymphalidae) were selected to demonstrate the possibilities of selective sensing offered by these natural nanoarchitectures. Each butterfly species gives characteristic response both for species, i.e., for its typical nanoarchitecture, and for the seven test vapors used. Fast response time, reproducible and concentration dependent signals are demonstrated.
Biologically inspired optics: analog semiconductor model of the beetle exoskeleton
Evolution in nature has produced through adaptation a wide variety of distinctive optical structures in many life forms. For example, pigment differs greatly from the observed color of most beetles because their exoskeletons contain multilayer coatings. The green beetle is disguised in a surrounding leaf by having a comparable reflection spectrum as the leaves. The Manuka and June beetle have a concave structure where light incident at any angle on the concave structures produce matching reflection spectra. In this work, semiconductor processing methods were used to duplicate the structure of the beetle exoskeleton. This was achieved by combining analog lithography with a multilayer deposition process. The artificial exoskeleton, 3D concave multilayer structure, demonstrates a wide field of view with a unique spectral response. Studying and replicating these biologically inspired nanostructures may lead to new knowledge for fabrication and design of new and novel nano-photonic devices, as well as provide valuable insight to how such phenomenon is exploited.
A look at some systemic properties of self-bioluminescent emission
Self-bioluminescent emission (SBE) is a type of biological chemiluminescence where photons are emitted as part of chemical reactions occurring during metabolic processes. This emission is also known as biophoton emission, ultraweak photon emission and ultraweak bioluminescence. This paper outlines research over the past century on some systemic properties of SBE as measured with biological detectors, photomultiplier detectors and ultra-sensitive imaging arrays. There is an apparent consensus in the literature that emission in the deep blue and ultraviolet (150-450nm) is related to DNA / RNA processes while emission in the red and near infrared (600-1000nm) is related to mitochondria and oxidative metabolisms involving reactive oxygen species, singlet oxygen and free radicals in plant, animal and human cells along with chlorophyll fluorescent decay in plants. Additionally, there are trends showing that healthy, unstressed and uninjured samples have less emission than samples that are unhealthy, stressed or injured. Mechanisms producing this emission can be narrowed down by isolating the wavelength region of interest and waiting for short-term fluorescence to decay leaving the ultraweak long-term metabolic emission. Examples of imaging this emission in healthy versus unhealthy, stressed versus unstressed, and injured versus uninjured plant parts are shown. Further discussion poses questions still to be answered related to properties such as coherence, photon statistics, and methodological means of isolating mechanisms.
High Dynamic Range Image rendering of color in chameleons' camouflage using optical thin films
High Dynamic Range Image (HDRI) rendering and animation of color in the camouflage of chameleons is developed utilizing thin film optics. Chameleons are a lizard species, and have the ability to change their skin color. This change in color is an expression of the physical and physiological conditions of the lizard, and plays a part in communication. The different colors that can be produced depending on the species include pink, blue, red, orange, green, black, brown and yellow. The modeling, simulation, and rendering of the color, which their skin incorporates, thin film optical stacks. The skin of a chameleon has four layers, which together produce various colors. The outside transparent layer has chromatophores cells, of two kinds of color, yellow and red. Next there are two more layers that reflect light: one blue and the other white. The innermost layer contains dark pigment granules or melanophore cells that influences the amount of reflected light. All of these pigment cells can rapidly relocate their pigments, thereby influencing the color of the chameleon. Techniques like subsurface scattering, the simulation of volumetric scattering of light underneath the objects surface, and final gathering are defined in custom shaders and material phenomena for the renderer. The workflow developed to model the chameleon's skin is also applied to simulation and rendering of hair and fur camouflage, which does not exist in nature.
Poster Session
icon_mobile_dropdown
Novel keys for analyzing physical features of light
The spatial coherence wavelets theory provides more insight into the understanding of interference and diffraction because they are the primary carriers of power and correlation of light. In this context, novel keys for analyzing the physical properties of light are revealed by these wavelets, as discussed in the present work. Particularly, the bright and the dark rays and related features as the energy flux vectors - parallel and anti-parallel to the Poynting vector, and the transverse energy transference, provide insight into the mechanism of energy distribution of a wavefield after diffraction and its dependence on spatial coherence properties of the field. These properties could be experimentally controlled by modulating the spatial coherence of the light, offering new possibilities of technological applications in subjects involving beam shaping.
Prediction of spectral shifts proportional to source distances by time-varying frequency or wavelength selection
Any frequency selective device with an ongoing drift will cause observed spectra to be variously and simultaneously scaled in proportion to their source distances. The reason is that detectors after the drifting selection will integrate instantaneous electric or magnetic field values from successive sinusoids, and these sinusoids would differ in both frequency and phase. Phase differences between frequencies are ordinarily irrelevant, and recalibration procedures at most correct for frequency differences. With drifting selection, however, each integrated field value comes from the sinusoid of the instantaneously selected frequency at its instantaneous received phase, hence the waveform constructed by the integration will follow the drifting selection with a phase acceleration given by the drift rate times the slope of the received phase spectrum. A phase acceleration is literally a frequency shift, and the phase spectrum slope of a received waveform is an asymptotic measure of the source distance, as the path delay presents phase offsets proportional to frequency times the distance, and eventually exceeding all initial phase differences. Tunable optics may soon be fast enough for realizing such shifts by Fourier switching, and could lead to pocket X-ray devices; sources continuously variable from RF to gamma rays; capacity multiplication with jamming and noise immunity in both fibre and radio channels, passive ranging from ground to deep space; etc.
New Doppler-free resonance in counterpropagating light waves
Sergei A. Zibrov, Leonid A. Sidorenkov, Peter A. Siushev, et al.
The resonance of saturated absorption in counterpropagating light fields is experimentally and theoretically studied. We focus on a case of parallel and linearly polarized waves, driving an open dipole transition in rubidium vapor. A new Doppler-free resonance within the saturated-absorption dip is revealed. The phenomenon can be gained only in absorption of strong wave in presence of weak one. The effect can not be explained basing on the previously known reasons. The results obtained can be found useful in metrology for the frequency and time standards.
Photo-real rendering of bioluminescence and iridescence in creatures from the abyss
The generation of photo-real renderings of bioluminescence is developed for creatures from the abyss. Bioluminescence results from a chemical reaction with examples found in deep-sea marine environments including: algae, copepods, jellyfish, squid, and fish. In bioluminescence, the excitation energy is supplied by a chemical reaction, not by a source of light. The greatest transparency window in seawater is in the blue region of the visible spectrum. From small creatures like single-cell algae, to large species of siphonophore Praya dubia (40m), luminescent phenomena can be produced by mechanical excitement from disturbances of objects passing by. Deep sea fish, like the Pacific Black Dragonfish are covered with photophores along the upper and lower surfaces which emits light when disturbed. Other animals like small squids have several different types of light organs oscillating at different rates. Custom shaders and material phenomena incorporate indirect lighting like: global illumination, final gathering, ambient occlusion and subsurface scattering to provide photo real images. Species like the Hydomedusae jellyfish, produce colors that are also generated by iridescence of thin tissues. The modeling and rendering of these tissues requires thin film multilayer stacks. These phenomena are simulated by semi-rigid body dynamics in a procedural animation environment. These techniques have been applied to develop spectral rendering of scenes outside the normal visible window in typical computer animation render engines.