Showing papers on "Birefringence published in 2006"
Patent•
28 Jun 2006
TL;DR: The polarizing beam splitter (PBS) as discussed by the authors is a beamforming beamforming system that is suitable for use in projection systems and displays and has a refractive index difference of less than about 0.15 units.
Abstract: The present invention provides a unique polarizing beam splitter (PBS) that is suitable for use in projection systems and displays. The PBS contains at least one prism having at least one major surface and having a refractive index of at least about 1.6 and a birefringent film disposed on the major surface of the prism. The birefringent film is a multi-layer film having at layers of at least a first material and a second material. After uniaxial stretching, the film exhibits a refractive index difference of less than about 0.15 units in the stretched direction.
290 citations
TL;DR: Bomzon et al. as discussed by the authors presented a Pancharatnam-Berry phase optical element for wave front shaping in the visible spectral domain, based on patterned liquid crystal technology, with the possibility of electro-optically switching between opposite helicities by controlling the handedness of the input circular polarization.
Abstract: We report the realization of a Pancharatnam-Berry phase optical element [Z. Bomzon, G. Biener, V. Kleiner, and E. Hasman, Opt. Lett. 27, 1141 (2002)], for wave front shaping working in the visible spectral domain, based on patterned liquid crystal technology. This device generates helical modes of visible light with the possibility of electro-optically switching between opposite helicities by controlling the handedness of the input circular polarization. By cascading this approach, fast switching among multiple wave front helicities can be achieved, with potential applications to multistate optical information encoding. The approach demonstrated here can be generalized to other polarization-controlled devices for wave front shaping, such as switchable lenses, beam splitters, and holographic elements.
274 citations
TL;DR: This achromatic wave plate demonstrates a huge frequency bandwidth (upsilonmax/upsilonmin approximately 7), and therefore can be applied to terahertz time domain spectroscopy and polarimetry.
Abstract: Phase retarders usually present a strong frequency dependence. We discuss the design and characterization of a terahertz achromatic quarter-wave plate. This wave plate is made from six birefringent quartz plates precisely designed and stacked together. Phase retardation has been measured over the whole terahertz range by terahertz polarimetry. This achromatic wave plate demonstrates a huge frequency bandwidth (upsilonmax/upsilonmin approximately 7), and therefore can be applied to terahertz time domain spectroscopy and polarimetry.
268 citations
TL;DR: In this paper, a high-intensity laser pulse is focused to ultra-relativistic intensity and polarizes the vacuum which then acts like a birefringent medium.
248 citations
TL;DR: In this article, temperature and external electrical field effects on propagation properties of a photonic liquid-crystal fibre composed of a solid-core photonic crystal fibre filled either with a prototype nematic liquid crystal characterized by extremely low (of the order of ~0.05) material birefringence or with a typical nematic pentylo-cyano-biphenyl, PCB (birefurringence of the order 2.2).
Abstract: The paper reports temperature and external electrical field effects on propagation properties of a photonic liquid-crystal fibre composed of a solid-core photonic crystal fibre filled either with a prototype nematic liquid crystal characterized by extremely low (of the order of ~0.05) material birefringence or with a typical nematic pentylo-cyano-biphenyl, PCB (birefringence of the order of ~0.2). The nematic liquid crystal was introduced into the micro holes of the photonic crystal fibre by the capillary effect. Depending on the liquid crystal material introduced into the micro holes and due to anisotropic properties of the photonic liquid-crystal fibre, switching between different guiding mechanisms controlled by temperature and an external electric field has been demonstrated. This creates great potential in fibre optic sensing and optical processing application.
189 citations
TL;DR: In this paper, the robust propagation, refraction and reflection of optical spatial solitons at the interface between two regions of a nematic liquid crystal is reported. And the authors demonstrate unprecedented nonlinear Goos-Hanchen lateral shifts in excess of 0.5 mm.
Abstract: Light filaments or optical spatial solitons are self-confined (non-spreading) beams that originate from the balance between diffraction and self-focusing in nonlinear optical media (those with a response dependent on the level of excitation)1,2,3. Owing to their ability to self-trap as well as to guide weaker signals (even if differing in colour or modulation format) within the waveguides or ‘light-pipes’ they induce, optical spatial solitons could form the basis of future all-optical processing networks4,5. One of the most interesting challenges in soliton propagation and engineering concerns light filaments incident on linear/nonlinear or nonlinear/nonlinear interfaces. Here we report the robust propagation, refraction and reflection of optical spatial solitons at the interface between two regions of a nematic liquid crystal. The ability to independently tune the optical properties of each region enables us to steer the beams by refraction and total internal reflection by as much as −18 and +22 degrees, respectively. Moreover, the extended (nonlocal) and anisotropic response of our system supports polarization healing of the solitons across the interface as well as non-specular filament reflection. Finally, exploiting the inherent and all-optically tunable birefringence, we demonstrate unprecedented nonlinear Goos–Hanchen lateral shifts in excess of 0.5 mm.
185 citations
TL;DR: The generation of a radially polarized laser beam from an extremely simple laser resonator including a c-cut Nd:YVO4 crystal as a laser medium by simply adjusting the distance between two cavity mirrors.
Abstract: We demonstrated the generation of a radially polarized laser beam from an extremely simple laser resonator including a c-cut Nd:YVO4 crystal as a laser medium. The oscillation in the radial polarization was based on the optical path difference between an extraordinary ray and an ordinary ray induced by the birefringence of the crystal. By simply adjusting the distance between two cavity mirrors, only the extraordinary ray became stable for the oscillation, resulting in the generation of a radially polarized beam. The beam was very stable even at low power output and is expected to be a promising radially polarized laser source because of its excellent simplicity.
179 citations
Book•
11 Sep 2006TL;DR: In this paper, the authors present a history of the use of light propagation in fiber propagation in a waveguide and the future use of a wave-guide in a fiber-waver.
Abstract: HISTORY OF POLYMER OPTICAL FIBERS Introduction Using Light for Telecommunications Glass Fibers Polymer Fibers The Future LIGHT PROPAGATION IN A FIBER WAVEGUIDE Introduction Bound Modes of Step-Index Fibers Multimode Waveguides Ray Propagation in a Graded-Index Medium Directional Couplers Conclusion Acknowledgments FABRICATING FIBERS Making Polymer Fibers by Extrusion Making Polymer Fiber by Drawing a Preform Birefringence of Drawn Fibers Mechanical Properties of Fibers THEORY OF REFRACTIVE INDEX AND LOSS Refractive Index Optical Loss Bending Loss Dispersion A Practical Example Polarization CHARACTERIZATION TECHNIQUES AND PROPERTIES Refractive Index Optical Loss Numerical Aperture Bandwidth TRANSMISSION, LIGHT SOURCES, AND AMPLIFIERS Transmission Displays Optical Amplification and Lasing OPTICAL SWITCHING Electrooptic Switching All-Optical Switching STRUCTURED FIBERS AND SPECIALTY APPLICATIONS Bragg Gratings Advanced Structured Fibers Photorefraction Stress and Temperature Sensors Chemical Sensors Appendix - Coupled Wave Equation SMART FIBERS AND MATERIALS Smart Materials Photomechanical Effects The Future of Smart Photonic Materials CONCLUSION Bibliography Index
172 citations
TL;DR: Native cellulose has been oriented in an ac electric field at both the macroscopic and colloidal level and cellulose whisker suspensions showed increasing birefringence with increasing field strength and displayed interference Newton colors that saturated at around 2000 V cm(-)(1).
Abstract: Native cellulose has been oriented in an ac electric field at both the macroscopic and colloidal level. Ramie fiber fragments suspended in chloroform have been shown to point along the field. Cellulose microcrystal suspensions in cyclohexane have also been allowed to evaporate in an electric field and have exhibited a high degree of orientation when further examined by TEM and electron diffraction. Similarly, cellulose whisker suspensions showed increasing birefringence with increasing field strength and displayed interference Newton colors that saturated at around 2000 V cm-1. A high degree of order of this suspension was also obtained by evaluating the induced birefringence with color charts.
167 citations
Patent•
10 Jul 2006TL;DR: In this paper, a high-resolution 2D-3D switchable autostereoscopic display apparatus is presented, which includes a backlight unit emitting light, a polarizer sheet changing the light emitted from the backlight units so that the light has only a specific polarization direction, and a polarization switch converting the direction of the polarization of incident light.
Abstract: A high resolution 2D-3D switchable autostereoscopic display apparatus includes: a backlight unit emitting light; a polarizer sheet changing the light emitted from the backlight unit so that the light has only a specific polarization direction; a polarization switch converting the direction of the polarization of incident light; a birefringent element array comprising a plurality of alternating first and second birefringent elements and changing the polarization direction of incident light so that the polarization of light transmitted by the first birefringent elements is perpendicular to the polarization of light transmitted by the second birefringent elements; a lenticular lens sheet separating and emitting incident light to a first eye viewing zone and a second eye viewing zone; and a display panel displaying an image.
166 citations
TL;DR: In this article, a two-element Lyot filter operating in the terahertz (THz) frequency range is demonstrated, which can be continuously tuned from 0.388to 0.564THz using magnetically controlled birefringence in nematic liquid crystals.
Abstract: A two-element tunable Lyot filter operating in the terahertz (THz) frequency range is demonstrated. The central bandpass frequency of the filter can be continuously tuned from 0.388to0.564THz (a fractional tuning range of 40%) using magnetically controlled birefringence in nematic liquid crystals. The transmission bandwidth is 0.1THz and the insertion loss of the present device is 8dB due to the scattering of LC molecules in the thick LC cells. This filter can be operated at room temperature.
TL;DR: It is demonstrated that the phase shifter works as an electrically switchable quarter-wave plate at 1 THz and can also be used as a electrically tuned phase compensator around the quarter- wave point near 1 THZ.
Abstract: Phase shift exceeding π/2 at 1 THz is demonstrated by using electrically controlled birefringence in a homeotropically aligned nematic liquid crystal (E7) cell, 570 μm in thickness. The driving voltage required for a phase shift of 90° is 125 V (rms). We demonstrate that the phase shifter works as an electrically switchable quarter-wave plate at 1 THz. The device can also be used as an electrically tuned phase compensator around the quarter-wave point near 1 THz.
TL;DR: Fiber-based high-speed polarization-sensitive Fourier domain optical coherence tomography (PS-FD-OCT) is developed at 840 nm wavelength using polarization modulation method and three dimensional phase retardation images show the potentials for applying the system to biological and medical studies.
Abstract: Fiber-based high-speed polarization-sensitive Fourier domain optical coherence tomography (PS-FD-OCT) is developed at 840 nm wavelength using polarization modulation method. The incident state of polarization is modulated along B-scan. The spectrometer has a polarizing beamsplitter and two line-CCD cameras operated at a line rate of 27.7 kHz. From the 0th and 1st orders of the spatial frequencies along the B-scanning, a depth-resolved Jones matrix can be derived. Since continuous polarization modulation along B-scan causes fringe washout, equivalent discrete polarization modulation is applied to biological measurements. For the demonstration, an in vitro chicken breast muscle, an in vivo finger pad, and an in vivo caries lesion of a human tooth are measured. Three dimensional phase retardation images show the potentials for applying the system to biological and medical studies.
TL;DR: In this article, the sensing head is formed by a long-period fiber grating combined with a high-birefringence fiber loop mirror, resulting in a configuration capable of temperature and strain discrimination.
Abstract: This work presents an alternative solution for simultaneous measurement of strain and temperature. The sensing head is formed by a long-period fiber grating combined with a high-birefringence fiber loop mirror resulting in a configuration capable of temperature and strain discrimination. These optical devices have opposite sensitivity responses when a variation of temperature and/or strain is applied. Maximum errors of plusmn0.8degC and plusmn21muepsiv are reported over 60 degC and 700-muepsiv measurement ranges, respectively
Book•
28 Nov 2006
TL;DR: In this article, the authors propose a method for separating polarization along a principal axis, which is based on the Jones concept, and a modified version of Birefringent Optics.
Abstract: Preface. 1 Polarized Light. 1.1 Introduction. 1.2 Concept of Light Polarization. 1.3 Description of The State of Polarization. 1.4 The Stokes Concept. 1.5 The Jones Concept. 1.6 Coherence and Polarized Light. References. 2 Electromagnetic Waves in Anisotropic Materials. 2.1 Introduction. 2.2 Analytical Background. 2.3 Time Harmonic Fields and Plane Waves. 2.4 Maxwell's Equations in Matrix Representation. 2.5 Separation of Polarizations for Inhomogeneous Problems. 2.6 Separation of Polarizations for Anisotropic Problems. 2.7 Dielectric Tensor and Index Ellipsoid. References. 3 Description of Light Propagation with Rays. 3.1 Introduction. 3.2 Light Rays and Wave Optics. 3.3 Light Propagation Through Interfaces (Fresnel Formula) . 3.4 Propagation Direction of Rays in Crystals. 3.5 Propagation Along A Principal Axis. 3.6 Rays at Isotropic-Anisotropic Interfaces. 3.7 Gaussian Beams. References. 4 Stratified Birefringent Media. 4.1 Maxwell Equations for Stratified Media. 4.2 Jones Formalism in Examples. 4.3 Extended Jones Matrix Method. 4.4 The 4x4 Berreman Method. 4.5 Analytical Solution for A Birefringent Slab. 4.6 Reflection and Transmission. References. 5 Space-Grid Time-Domain Techniques. 5.1 Introduction. 5.2 Description of the FDTD Method. 5.3 Implementation and Boundary Conditions. 5.4 Rigorous Optics for Liquid Crystals. References. 6 Organic Optical Materials. 6.1 Introduction. 6.2 Polymers for Optics. 6.3 Physical Properties of Polymers. 6.4 Optical Properties of Polymers. 6.5 Liquid Crystal Phases. 6.6 Liquid Crystal Polymers. 6.7 Birefringence in Isotropic Materials. 6.8 Form Birefringence. 6.9 Order-Induced Birefringence. 6.10 Optical Properties of Liquid Crystals and Oriented Polymers. References. 7 Practical Polarization Optics with the Microscope. 7.1 Introduction. 7.2 Microscope Characteristics. 7.3 Polarization Microscope. 7.4 Polarizers. 7.5 Polarization Colors. 7.6 Compensation and Retardation Measurement. 7.7 Conoscopy. 7.8 Local Polarization Mapping. References. 8 Optics of Liquid Crystal Textures. 8.1 Introduction. 8.2 Calculation of Liquid Crystal Director Distributions. 8.3 Optical Properties of Uniform Textures. 8.4 Optical Properties of Liquid Crystal Defects. 8.5 Surface Line Defects in Nematics. 8.6 Defects in Smectic Phases. 8.7 Confined Nematic Liquid Crystals. 8.8 Instabilities in Liquid Crystals. 8.9 Deformation of Liquid Crystal Directors by Fringing Fields. 8.10 Resolution Limit of Switchable Liquid Crystal Devices. 8.11 Switching in Layered Phases. References. 9 Refractive Birefringent Optics. 9.1 Birefringent Optical Elements. 9.2 Fabrication of Refractive Components. 9.3 Optical Properties of Modified Birefringent Components. 9.4 Liquid Crystal Phase Shifters. 9.5 Modal Control Elements. 9.6 Interferometers Based on Polarization Splitting. 9.7 Birefringent Microlenses. 9.8 Electrically Switchable Microlenses. References. 10 Diffractive Optics with Anisotropic Materials. 10.1 Introduction. 10.2 Principles of Fourier Optics. 10.3 Polarization Properties. 10.4 Diffraction at Binary Gratings. 10.5 Concepts and Fabrication. 10.6 Diffractive Elements Due to surface Modifications. 10.7 Electrically Switchable Gratings. 10.8 Switchable Diffractive Lenses. References. 11 Bragg Diffraction. 11.1 Reflection by Multilayer Structures. 11.2 Polymer Films. 11.3 Giant Polarization Optics. 11.4 Reflection by Cholesteric Liquid Crystals. 11.5 Color Properties of Cholesteric Bragg Reflectors. 11.6 Apodization of Cholesteric Bragg Filters. 11.7 Reflection by Dispersed Cholesteric Liquid Crystals. 11.8 Depolarization Effects by Polymer Dispersed Cholesteric Liquid Crystals. 11.9 Defect Structures in Cholesteric Bragg Reflectors. 11.10 Structured Cholesteric Bragg Filters. 11.11 Plane Wave Approach to the Optics of Blue Phases. References. Index.
TL;DR: The far-infrared properties of spruce wood are examined with a terahertz time-domain spectrometer and the solid wood is shown to exhibit both birefringence and diattenuation.
Abstract: The far-infrared properties of spruce wood are examined with a terahertz time-domain spectrometer. The solid wood is shown to exhibit both birefringence and diattenuation. The birefringence properties are sufficient for construction of a quarter-wave plate operating at
0.36 THz, and a half-wave plate operating at
0.71 THz. The origin of the birefringence is attributed to preferential fiber orientation within the wood. Similar birefringence is observed in lens paper in which the fibers are preferentially oriented in one direction.
TL;DR: A high birefringence of over 0.21 for the yttrium vanadate (YVO4) crystal in the middle wavelength infrared (i.e., 3-5 microm) was measured.
Abstract: A high birefringence of over 0.21 for the yttrium vanadate (YVO4) crystal in the middle wavelength infrared (i.e., 3-5 µm) was measured. A Fourier transform infrared spectrometer was employed in the channel spectra technique to obtain the measurements.
TL;DR: Self-assembled, sub-wavelength periodic structures are induced in fused silica by a tightly focused, linearly polarized, femtosecond laser beam and spatial coherence of these nanogratings in the plane perpendicular to the beam propagation direction is demonstrated.
Abstract: Self-assembled, sub-wavelength periodic structures are induced in fused silica by a tightly focused, linearly polarized, femtosecond laser beam Two different types of periodic structures, the main one with period (ΛE) in the direction of the laser beam polarization and the second with period (Λk) in the direction of the light propagation, are identified from the cross-sectional images of the modified regions using scanning electron microscopy We demonstrate the spatial coherence of these nanogratings in the plane perpendicular to the beam propagation direction The range of effective pulse energy which could produce nanogratings narrows when the pulse repetition rate of writing laser increases The period ΛE is proportional to the wavelength of the writing laser and period Λk in the head of the modified region remains approximately the wavelength of light in fused silica
TL;DR: In this article, the authors report a strong polarization dependent coupling behavior of fiber Bragg gratings with excessively tilted structures up to 81 degrees and implement a novel twist sensor, showing high torsion sensitivity.
Abstract: We report a strong polarization dependent coupling behavior of fiber Bragg gratings with excessively tilted structures up to 81deg. This unique property has been utilized to implement a novel twist sensor, showing high torsion sensitivity. The twist induced light coupling interchange between the two birefringence modes makes it possible to interrogate such a sensor using low-cost intensity demodulation technique
TL;DR: In this article, the single-polarization single-mode (SPSM) operation of a highly birefringent (HB) photonic crystal fiber (PCF) was investigated in detail by using a full-vector finite-element method (FEM) with anisotropic perfectly matched layers (PMLs).
Abstract: Single-polarization single-mode (SPSM) operation of a highly birefringent (HB) photonic crystal fiber (PCF) is investigated in detail by using a full-vector finite-element method (FEM) with anisotropic perfectly matched layers (PMLs). The cutoff wavelengths of the two linearly polarized principal states can be designed by varying the structure parameters of the PCF. The confinement loss and splice loss to standard single-mode fiber for particular SPSM PCFs are calculated and optimized at both 1.30 and 1.55 /spl mu/m.
TL;DR: In this paper, the authors demonstrate that it is possible to synthesize a polymer that exhibits no orientational birefringence and no photoelastic birerringence using two methods: monomers and an anisotropic dopant.
Abstract: Here we demonstrate, for the first time, that it is possible to synthesize a polymer that exhibits no orientational birefringence and no photoelastic birefringence using two methods. In these methods, the contributions of monomers and an anisotropic dopant to orientational birefringence and photoelastic birefringence are analyzed experimentally, after which the composition of a ternary copolymer or a binary copolymer including the dopant is adjusted, based on the results, to compensate for both types of birefringence. By the methods and fine adjustment of the composition, we synthesized poly(methyl methacrylate (MMA)/2,2,2-trifluoroethyl methacrylate (3FMA)/benzyl methacrylate = 52.0/42.0/6.0(w/w/w)) and poly(MMA/3FMA = 85.0/15.0(w/w)) containing 2.8 wt % of trans-stilbene that exhibited close to zero birefringence.
TL;DR: In this article, the two-way propagation of depolarized radio waves that scatter at both isotropic and anisotropic boundaries is studied. And the authors demonstrate how COF affects the radar signals in terms of radar polarization and frequency and compare the simulated features with VHF radar data obtained at two contrasting inland sites in East Antarctica.
Abstract: Crystal-orientation fabric (COF) has a large influence on ice-sheet flow. Earlier radar studies have shown that COF-based birefringence occurs within ice sheets. Radio-wave scattering in polar ice results from changing physical properties of permittivity and conductivity that arise from differing values of density, acidity and COF. We present an improved mathematical model that can handle all these phenomena together. We use this matrix-based model to study the two-way propagation of depolarized radio waves that scatter at both isotropic and anisotropic boundaries. Based on numerical simulations, we demonstrate how COF affects the radar signals in terms of radar polarization and frequency. We then compare the simulated features with VHF radar data obtained at two contrasting inland sites in East Antarctica, where COF is known from ice-core studies. These two sites are Dome Fuji, located near a dome summit, and Mizuho, located in a converging ice-flow region. Data at Dome Fuji are dominated by typical features resulting from birefringence. In contrast, both birefringence and anisotropic scattering affect the radar data at Mizuho. We argue that radar methods can be used to determine principal axes and strength of birefringence in the ice sheets.
TL;DR: In this article, the authors evaluate the measurement of flow-induced birefringence (orientation) under extension in microfluidic cross-slots, whose flow kinematics was examined by microparticle image velocimetry.
Abstract: The rheo-optical analysis of polymer solutions and melts is a critical tool in elucidating their molecular response to flow fields. We therefore evaluate the measurement of flow-induced birefringence (orientation) under extension in microfluidic cross-slots, whose flow kinematics was examined by microparticle image velocimetry. The effects of planar extension on the (non)linear viscoelasticity of wormlike micellar surfactant solutions (comprising either cetyltrimethylammonium bromide or cetylpyridinium chloride in aqueous sodium salicylate) were measured. The effect of wall shear was found to be negligible compared to extension. The birefringence is linear (indicating the validity of the stress−optical rule) for very small extensional Weissenberg numbers, as expected. This rule fails, however, when a sharp birefringence band appears at modest Weissenberg number (indicating the alignment of wormlike micelles along the outflow direction). Experiments that measure average birefringence may misidentify the po...
TL;DR: In this paper, the authors report the different response to temperature displayed by isotropic femtosecond written structures (type I_fs), and anisotropic ones (type II_fs) which are characterized by the presence of a self-assembled subwavelength periodic structure within the irradiated volume.
Abstract: In this letter we report the different response to temperature displayed by isotropic femtosecond written structures (type I_fs), and anisotropic ones (type II_fs), which are characterized by the presence of a self-assembled subwavelength periodic structure within the irradiated volume. We observe that the anisotropic structures display an extraordinary annealing behavior, namely, their photoinduced change in refractive index increases with the annealing temperature. We explain our experimental results with a theoretical model.
TL;DR: The dispersive characteristics of a photonic crystal fiber enhanced with a liquid crystal core are studied using a planewave expansion method and numerical results demonstrate that by appropriate design such fibers can function in a single-mode/single-polarization operation, exhibit high- or low- birefringence behavior, or switch between an on-state and an off-state.
Abstract: The dispersive characteristics of a photonic crystal fiber enhanced with a liquid crystal core are studied using a planewave expansion method. Numerical results demonstrate that by appropriate design such fibers can function in a single-mode/single-polarization operation, exhibit high- or low- birefringence behavior, or switch between an on-state and an off-state (no guided modes supported). All of the above can be controlled by the application of an external electric field, the specific liquid crystal anchoring conditions and the fiber structural parameters.
TL;DR: In this paper, the authors present terahertz time-domain spectroscopy (TDS) measurements on injection molded liquid crystalline polymers (LCPs) and find that the direction of the optical axis varies within the injection molded sample.
Abstract: The authors present terahertz time-domain spectroscopy (TDS) measurements on injection molded liquid crystalline polymers (LCPs). Pure LCP yields a strong birefringence of Δn=0.2. They find that the direction of the optical axis varies within the injection molded sample. By terahertz (polarization) imaging domains of certain directions of the optical axis could be observed. These strongly depend on the mold geometry. Since the alignment of particles and rodlike polymer molecules tend to follow the melt flow during injection molding, terahertz TDS can be used to analyze injection molded LCP parts and control the process performance.
TL;DR: In this article, a tunable high-power high-brightness linearly polarized vertical-external-cavity surface-emitting lasers (VECSELs) with a 20nm tuning range and narrow linewidth is demonstrated at room temperature.
Abstract: We report on the development and the demonstration of tunable high-power high-brightness linearly polarized vertical-external-cavity surface-emitting lasers (VECSELs). A V-shaped cavity, in which the antireflection-coated VECSEL chip (active mirror) is located at the fold, and a birefringent filter are employed to achieve a large wavelength tuning range. Multiwatt cw linearly polarized TEM00 output with a 20nm tuning range and narrow linewidth is demonstrated at room temperature.
Patent•
01 Jun 2006TL;DR: In this article, a first polarizer for polarizing reflected or fluorescent light from a specimen, a first birefringence wave plate for separating the light from the first polarizing into two beams along a polarizing direction, a second polarizer to polarize the two beams of the first wave plate from the second wave plate, and a third wave plate to polarise the four beams from the two wave plates.
Abstract: The present invention relates to confocal self-interference microscopy. The confocal self-interference microscopy further includes a first polarizer for polarizing reflected or fluorescent light from a specimen, a first birefringence wave plate for separating the light from the first polarizer into two beams along a polarizing direction, a second polarizer for polarizing the two beams from the first birefringence wave plate, a second birefringence wave plate for separating the two beams from the second polarizer into four beams along the polarizing direction, and a third polarizer for polarizing the four beams from the second birefringence wave plate, in the existing confocal microscopy. Optic-axes of the first and second birefringence wave plates exist on the same plane, optic-axes of the first and second birefringence wave plates are inclined from an optical axis of the entire optical system at a predetermined angle, and self-interference spatial periods of the first and second birefringence wave plates are different from each other.
TL;DR: In this paper, a novel silicon-on-insulator (SOI) ring resonator design is described that uses a 2 /spl times 2 multimode interference coupler to achieve polarization-independent coupling, and cladding stress induced birefringence control to eliminate the difference in round-trip phase accumulation between the transverse-electric and transversemagnetic polarized modes.
Abstract: A novel silicon-on-insulator (SOI) ring resonator design is described that uses a 2 /spl times/ 2 multimode interference coupler to achieve polarization-independent coupling, and cladding stress induced birefringence control to eliminate the difference in round-trip phase accumulation between the transverse-electric and transverse-magnetic polarized modes. The design parameters are determined for polarization-independent SOI ring resonators with couplers having a 50 : 50 or 15 : 85 splitting ratio, and 1.5-/spl mu/m ridge height and width. As designed, the resonators offer a polarization-independent free-spectral range of 0.5 nm for a ring radius of 200 /spl mu/m, and a quality factor Q as high as 55 000.