共查询到20条相似文献,搜索用时 602 毫秒
1.
A real-time measurement method for the retardation of an eighth-wave plate is proposed. The collimated laser beam is split using a Glan Taylor polarizer with two side escape windows. The reflected sub-beam is detected using a detector, whereas the transmitted sub-beam passes through the quarter-wave plate and the eighth-wave plate of interest. Then, it is reflected by the mirror and passes reversely through the eighth-and quarter-wave plates. Finally, it is analyzed using the Glan Taylor polarizer and detected using another detector. With two detection signals, the retardation is resolved and found to be independent of the fast-axis direction, initial intensity, and circuit parameters. In the experiment, a crystal quartz sample is measured at different fast-axis angles. The standard deviation of the retardation is 0.9 o . The usefulness of the method is verified. 相似文献
2.
A detailed analysis of the polarization eigenmodes of a QHQ retarder (a half-wave plate sandwiched between two identical quarter-wave plates) is presented. These are shown to be discontinuous as a function of the orientation of the half-wave plate, as a function of the wavelength of incident light and as a function of the retardation of the middle waveplate. 相似文献
3.
S. De Nicola P. Ferraro A. Finizio G. Pierattini 《Applied physics. B, Lasers and optics》1995,60(4):405-407
We describe an optical heterodyne polarization interferometer that can be efficiently used for the precision measurement of the change in the state of polarization of a light wave induced by polarizing optical devices. This technique is used to measure the change with wavelength of the phase retardation of a quarter-wave plate. A theoretical derivation is presented to permit computation of the wavelength dependence of the phase shift induced by a quarter-wave plate. 相似文献
4.
综合等效介质理论和表面等离子激元(SPP)Bloch模型,对比分析了两种新的亚波长光栅结构:二维矩形金属光栅和二维椭圆柱金属光栅。利用时域有限差分(FDTD)算法,对比分析了两种结构的透射率及其相位延迟与入射光波长及偏振角变化的关系,尤其两种结构实现λ/4波片功能所对应的透射特性。仿真结果表明,当入射光偏振角为75°时,两种结构均可实现λ/4波片功能,此时二维矩形和椭圆柱金属光栅的透射率分别为0.77和0.67,表明二维矩形金属光栅比椭圆柱光栅具有更好的透射效果。对应550~800nm的入射波长,两种光栅在各自允许的入射偏振角范围内均表现了较为平坦的宽带透射特性。 相似文献
5.
简要介绍了激光纵模分裂的基本原理,研究了腔内含有1个和2个1/4波片时产生Nd∶YAG激光纵模分裂的规律。实验结果表明:在1064nm Nd∶YAG激光的腔内放置一个1/4波片时,每一激光纵模分裂为2个正交的线偏振模,在波片表面垂直于激光光线的条件下,纵模分裂量(即频率差或波长差)恰好等于激光纵模间隔的一半;当在Nd∶YAG激光腔内沿垂直光线方向平行放置2个1/4波片时,也能产生纵模分裂现象,其纵模分裂量取决于2波片快(慢)轴之间的夹角。在0°~ 90°范围内调节角度,可使纵模分裂量在一个激光纵模间隔内线性调谐。实验结果与理论分析相吻合。 相似文献
6.
Zheng Ping Wang Qing Bo Li Qiao Tan Zong Jun Huang Jin Hui Shi 《Optics & Laser Technology》2004,36(4):285-290
A novel and simple method used for measurement of retardance of a quarter-wave plate employing two polaroids and a right-angle prism is reported. The theoretical analysis of the principle is given taking the Jones matrix as a mathematical tool. The uncertainty of the method is theoretically analyzed. An application example is also given. The measured result of the example is verified with a test. The main advantage of this method is that it can completely determine the retardance value, which overcomes the shortcomings of the existing methods reported before for determining only the multi-value function values, such as cosine or tangent value of the retardance. In addition, this method is also accurate, easy to operate and can also be used for the retardance measurement of other retardation plates. 相似文献
7.
The Fourier transform method, widely applied in photomechanics for the automated analysis of interferometric fringe patterns, has been recently extended to the photoelastic isochromatic fringe patterns analysis. Unfortunately, its use in photoelasticity involves some limitations that have not been completely highlighted in literature. This work deals with the influence of the quarter-wave plate tolerance on the evaluation of the retardation. Both theoretical and experimental analyses have shown that the quarter-wave plate error does not affect the retardation only if the principal stress directions in the model and in the carrier are aligned. In general, instead, the tolerance of the quarter-wave plates leads to an amplification of the retardation error due to the influence of the isoclinics with a subsequent restriction of the field in which the method can be applied. For instance, using common quarter-wave plates and tolerating a maximum retardation error of about 0.03 fringe order, than the Fourier transform method cannot be applied as a full-field technique but only in the model zones in which the misalignment between the principal stresses in the model and in the carrier is less than 15°. 相似文献
8.
Half-wave retarders are primarily used in rotating the plane of polarization of polarized light. These retarders usually exhibit strong wavelength dependence. In this paper, the design and characteristics of an achromatic half-wave plate, formed by a cascaded system of birefringent plates, have been studied. Pancharatnam proposed a combination of three retarders in series and discussed the possibility of fabricating reasonably good achromatic quarter-wave plate with a suitable combination of their retardance. The system studied here is similar in construction to Pancharatnam configuration and behaves as an achromatic half-wave plate over a wide spectral range. The proposed configuration exhibits a maximum variation of only about ±1.4 degree over the entire wavelength range of 500–750 nm. In our analysis we have used Jones matrix formalism for the derivation of the general expression for the equivalent retardation and the azimuth of the combination. 相似文献
9.
10.
Terahertz achromatic quarter-wave plate 总被引:3,自引:0,他引:3
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. 相似文献
11.
James W. Lamb Mathew C. Carter François Mattiocco 《International Journal of Infrared and Millimeter Waves》2001,22(5):679-685
A series of grooved dielectric quarter-wave plates was made for radio astronomical Zeeman splitting observations at millimeter wavelengths. To meet the stringent requirements on reflection and polarization purity, a design method was formulated based on optimization of multiple reflections. The method solves the problem of achieving low reflections for both polarization components while attaining high purity of circular polarization. Several plates have been manufactured, tested, and used successfully for astronomical observations. 相似文献
12.
During the last decades, several methods have been proposed to automate photoelastic analyses. Some procedures are based on the circularly polarised light by using quarter wave plates. However, quarter wave plates are typically matched for a specific wavelength, and an error is introduced at different wavelengths. The error of quarter wave plates affects the measurement of isochromatic and isoclinic data. In this paper, the influence of the errors of quarter wave plates in some of the most common automated photoelastic methods is reviewed. The errors in the photoelastic data are given and the procedures to reduce, or eliminate, them are also suggested. 相似文献
13.
14.
We present a new circular heterodyne interferometer with electro-optic modulation for measurement of the optical linear birefringence. It enables the measurement of not only the phase retardation but also the principal angle. The measurement procedure is carried out in two steps. In the first step of measurements, we use the electro-optic modulated circular heterodyne interferometer and the phase-lock technique to precisely measure the principal axis angle. After rotating the analyzer in the setup, the phase retardation is determined also by the phase-lock technique. The compact configuration requires only a photodetector and two simple phase-lock extractions to determine the principal axis angle and the phase retardation. The validity of the proposed design is demonstrated by measurement of the principal axis angle and phase retardation of a quarter-wave plate sample. The root-mean-square resolutions for the principal axis angle and phase retardation are found to be 0.0396° and 0.0796°, respectively, with corresponding dynamic ranges of 0–180° and 0–180°. 相似文献
15.
16.
Plasmonic quarter-wave plate 总被引:1,自引:0,他引:1
Here we present a strategy for designing wave plates utilizing resonances of subwavelength apertures in metallic films. Specifically, we show that it is possible to tune the geometry in a periodic array of cross-shaped apertures in a silver film to produce a quarter-wave plate at a particular wavelength in the near-infrared. This is achieved by introducing an asymmetry into the lengths of the arms of the crosses. 相似文献
17.
A method for measuring retardation of a quarter-wave plate based on normalized secondary harmonic component is proposed, and the measuring principle is analyzed. The optical measuring system is composed of a laser, a polarizer, a phase modulator, the quarter-wave plate to be measured, an analyzer and a detector. The azimuths of the transmission axes of the polarizer and the analyzer with respect to the modulating axis of the phase modulator are +45°, 0°, respectively. The retardation of the quarter-wave plate is calculated precisely using the normalized secondary harmonic components prior to and after 22.5° rotation of the quarter-wave plate. In this method, the major axis position of the quarter-wave plate is not required to be known in advance, and the measured retardation is independent of the intensity fluctuation of the light source. The feasibility of the method is verified by the experiments. 相似文献
18.
It has long been recognized 1,2,3,4,5 in measuring relative intensities and depolarization ratios of Raman lines that prism and grating spectrometers have different transmittances for light polarized parallel (T∥) and perpendicular (T⊥) to the slit. Several methods have been used to give equal instrument response to parallel and perpendicular polarization. Stitt and Yost3 used a Nicol prism parallel to the high-transmittance direction of the spectrometer, combined with a rotatable mica half-wave plate to transmit either vector to the Nicol prism. This method has the advantage of having a higher spectrometer transmittance, but the mica plate gives exact half-wave retardation at only a single wavelength. A mica quarter-wave plate 4,5 averages the transmittances of the spectrometer for the two polarization directions, but is also wavelength dependent. Virtually achromatic circular polarizers have been designed and constructed 6,7, but these devices are too bulky and expensive for the clear apertures needed for fast spectrometers. 相似文献
19.
20.
Cyclic errors that are due to optical leakage limit the precision of displacement measurements made with optical interferometers. A method for real-time estimation of leakage components is introduced and is used to implement a novel passive technique for suppression of cyclic nonlinearities that uses only adjustments of existing polarizers and quarter-wave plates. This approach is used to reduce the cyclic error from 3 nm to 300 pm for an interferometer operating at a wavelength of 1320 nm. 相似文献