- 标题
- 摘要
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- 实验方案
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New ellipsometric approach for determining small light ellipticities
摘要： Control of the coherent light polarization is always one of the important topics in laser physics and engineering. We propose an exact ellipsometric method for investigation of coherent light with small ellipticity. Using compensators with phase retardations providing maximum measurement accuracy for the selected ellipticity range is suggested. The method allows us to avoid taking into account the interference of multiple internal reflections of coherent light. The accuracy of the method increases with decreasing of the compensator phase retardation. Using light with a given ellipticity, we have measured the ellipticity of the light in the range of 3.5×10?? to 5.0×10?3. The relative error of the ellipticity measuring in the range of 8.0×10?? to 5.0×10?3 turns out does not exceed 0.02.
关键词： Polarization,Ellipsometry,Coherence
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Conference on Antenna Measurements & Applications (CAMA) - Va?ster?s (2018.9.3-2018.9.6)] 2018 IEEE Conference on Antenna Measurements & Applications (CAMA) - Design of Low-profile Antenna with Multi-directional Beam
摘要： An planar antenna having a low-pro?le structure using loop elements is proposed. The proposed antenna is vertically polarized and has four directional beams for sensor nodes. The thickness of the antenna is only 3.2 mm (0.11 effective wavelength) resulting in a low-pro?le structure. Simulated and measured average gain of 8.0 dBi and 5.6 dBi are obtained, respectively.
关键词： wireless sensor network,sensor node,low-pro?le antenna,vertical polarization,multi-directional beam
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE International Workshop on Electromagnetics: Applications and Student Innovation Competition (iWEM) - Nagoya (2018.8.29-2018.8.31)] 2018 IEEE International Workshop on Electromagnetics:Applications and Student Innovation Competition (iWEM) - Kanji Patch Antennas
摘要： This article introduces the basic concepts of Kanji patch antennas. We use two novel L-probe-fed Guo- and Meng-shaped patches operating in circular polarization as examples. The main parameters of these symmetrical and asymmetrical shaped patch antennas were studied and optimized via computer-aided simulation.
关键词： Kanji patch antennas,circular polarization,L-shaped feeding probe,artistic antenna
更新于2025-09-23 15:23:52
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Precision mapping the topological bands of 2D spin-orbit coupling with microwave spin-injection spectroscopy
摘要： To investigate the band structure is one of the key approaches to study the fundamental properties of a novel material. We report here the precision band mapping of a 2-dimensional (2D) spin-orbit (SO) coupling in an optical lattice. By applying the microwave spin-injection spectroscopy, the band structure and spin-polarization distribution are achieved simultaneously. The band topology is also addressed with observing the band gap close and re-open at the Dirac points. Furthermore, the lattice depth and the Raman coupling strength are precisely calibrated with relative errors in the order of 10?3. Our approach could also be applied for exploring the exotic topological phases with even higher dimensional system.
关键词： Topological band,Microwave spin-injection spectroscopy,Spin polarization,Topological phase transition,2D spin-orbit coupling
更新于2025-09-23 15:23:52
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Simultaneous acquisition of polarimetric SVBRDF and normals
摘要： Capturing appearance often requires dense sampling in light-view space, which is often achieved in specialized, expensive hardware setups. With the aim of realizing a compact acquisition setup without multiple angular samples of light and view, we sought to leverage an alternative optical property of light, polarization. To this end, we capture a set of polarimetric images with linear polarizers in front of a single projector and camera to obtain the appearance and normals of real-world objects. We encountered two technical challenges: First, no complete polarimetric BRDF model is available for modeling mixed polarization of both specular and diffuse reflection. Second, existing polarization-based inverse rendering methods are not applicable to a single local illumination setup since they are formulated with the assumption of spherical illumination. To this end, we first present a complete polarimetric BRDF (pBRDF) model that can define mixed polarization of both specular and diffuse reflection. Second, by leveraging our pBRDF model, we propose a novel inverse-rendering method with joint optimization of pBRDF and normals to capture spatially-varying material appearance: per-material specular properties (including the refractive index, specular roughness and specular coefficient), per-pixel diffuse albedo and normals. Our method can solve the severely ill-posed inverse-rendering problem by carefully accounting for the physical relationship between polarimetric appearance and geometric properties. We demonstrate how our method overcomes limited sampling in light-view space for inverse rendering by means of polarization.
关键词： polarization,SVBRDF acquisition
更新于2025-09-23 15:23:52
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Acquiring spatially varying appearance of printed holographic surfaces
摘要： We present two novel and complimentary approaches to measure diffraction effects in commonly found planar spatially varying holographic surfaces. Such surfaces are increasingly found in various decorative materials such as gift bags, holographic papers, clothing and security holograms, and produce impressive visual effects that have not been previously acquired for realistic rendering. Such holographic surfaces are usually manufactured with one dimensional diffraction gratings that are varying in periodicity and orientation over an entire sample in order to produce a wide range of diffraction effects such as gradients and kinematic (rotational) effects. Our proposed methods estimate these two parameters and allow an accurate reproduction of these effects in real-time. The first method simply uses a point light source to recover both the grating periodicity and orientation in the case of regular and stochastic textures. Under the assumption that the sample is made of the same repeated diffractive tile, good results can be obtained using just one to five photographs on a wide range of samples. The second method is based on polarization imaging and enables an independent high resolution measurement of the grating orientation and relative periodicity at each surface point. The method requires a minimum of four photographs for accurate results, does not assume repetition of an exemplar tile, and can even reveal minor fabrication defects. We present point light source renderings with both approaches that qualitatively match photographs, as well as real-time renderings under complex environmental illumination.
关键词： Diffraction,real-time rendering,spectral,polarization,wave optics
更新于2025-09-23 15:23:52
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Modified Sagnac imaging spectropolarimeter for full linear Stokes parameters
摘要： A modified Sagnac imaging spectropolarimeter is conceptually described. It consists of a spectral-polarimetric modulator, a modified Sagnac interferometer with large optical path difference, and a CCD camera. This design modulates the Stokes components of the input light into different wave numbers and obtains the modulated interferogram in snapshot mode, and the spectra of the Stokes components can be separated and demodulated from the interferogram. The performance of the system is demonstrated through a numerical simulation, and a novel method is proposed to detect the polarization parameters including the degree of polarization and polarization direction for eliminating the aliasing effects between linear Stokes parameters. Compared with the existing imaging spectrometers, the modified Sagnac imaging spectropolarimeter can acquire one-dimensional spatial information and its full linear spectropolarimetric information in one exposure, and some other spatial information can be obtained by push-broom mode.
关键词： imaging spectropolarimeter,snapshot mode,Stokes parameters,polarization,Sagnac interferometer
更新于2025-09-23 15:23:52
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Compensation of Distortions of Polarization Characteristics of Ring Resonators
摘要： The reasons of occurrence of polarization mode distortions and methods of their compensation are investigated. It is demonstrated that sensitivity of lasers with ring resonator to magnetic field may be reduced, if effect of induced polarization anisotropy to be compensated by means of installation of a mirror in resonator in certain position, which complies with the minimum ellipticity angle.
关键词： polarization characteristics of interference mirrors,ring optical resonators,phase anisotropy,information optics
更新于2025-09-23 15:23:52
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3D Mueller-Matrix Diffusive Tomography of Polycrystalline Blood Films for Cancer Diagnosis
摘要： The decomposition of the Mueller matrix of blood films has been carried out using differential matrices with polarized and depolarized parts. The use of a coherent reference wave is applied and the algorithm of digital holographic reconstruction of the field of complex amplitudes is used. On this basis, the 3D Mueller-matrix diffuse tomography method—the reconstruction of distributions of fluctuations of linear and circular birefringence of depolarizing polycrystalline films of human blood is analytically justified and experimentally tested. The dynamics of the change in the magnitude of the statistical moments of the first-fourth order, which characterize layer-by-layer distributions of fluctuations in the phase anisotropy of the blood film, is examined and analyzed. The most sensitive parameters for prostate cancer are the statistical moments of the third and fourth orders, which characterize the asymmetry and kurtosis of fluctuations in the linear and circular birefringence of blood films. The excellent accuracy of differentiation obtained polycrystalline films of blood from healthy donors and patients with cancer patients was achieved.
关键词： polarimetry,Mueller-matrix,blood,cancer diagnostics,polarization
更新于2025-09-23 15:23:52
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Monitoring dynamic collagen reorganization during skin stretching with fast polarization-resolved SHG imaging
摘要： The mechanical properties of biological tissues are strongly correlated to the specific distribution of their collagen fibers. Monitoring the dynamic reorganization of the collagen network during mechanical stretching is however a technical challenge because it requires mapping orientation of collagen fibers in a thick and deforming sample. In this work, a fast polarization-resolved SHG microscope is implemented to map collagen orientation during mechanical assays. This system is based on line-to-line switching of polarization using an electro-optical modulator and works in epidetection geometry. After proper calibration, it successfully highlights the collagen dynamic alignment along the traction direction in ex vivo murine skin dermis. This microstructure reorganization is quantified by the entropy of the collagen orientation distribution as a function of the stretch ratio. It exhibits a linear behavior, whose slope is measured with a good accuracy. This approach can be generalized to probe a variety of dynamic processes in thick tissues.
关键词： biomechanics,multiphoton microscopy,skin,polarization,collagen
更新于2025-09-23 15:23:52