两步广义相移干涉术的光学实验验证

提出了一种基于两步广义相移干涉术的波前再现技术以及基于衍射场统计特性的未知相移值提取算法,并且进行了光学实验验证.该方法中可仅利用两幅干涉图及一次不需精确预设的未知相移,参照物光光强和参考光光强,即可通过计算提取真实的相移量,进而恢复出物波波前复振幅,而无需借助傅里叶谱分析或数字滤波等操作.在光学实验中,对借助于空间光调制器（SLM）的间接输入和三维漫反射物体直接输入两种情况进行了详细地研究,得到的光学实验结果验证了所提方案的有效性和可行性. 关键词： 信息光学 相移干涉术 波前再现 数字图像处理     

Wavefront reconstruction by two-step generalized phase-shifting interferometry

A wavefront reconstruction method by two-step generalized phase-shifting interferometry (GPSI) with blind phase shift extraction algorithm is verified by both the computer simulations and optical experiments. This method can retrieve complex object wave field by using two interferograms, the recorded object and reference wave intensities, and an unknown phase shift without additional processing. The simulations with irregular wavefronts have shown the effectiveness and high accuracy of this method for blind phase-shift extraction and wavefront reconstruction over a wide range of phase-shifts, while the optical experiments for both the direct and indirect objects have yielded satisfactory results with a higher resolution of reconstructed image than those reported recently.     

Simple direct extraction of unknown phase shift and wavefront reconstruction in generalized phase-shifting interferometry: algorithm and experiments

An algorithm to extract the arbitrary unknown phase shift and then reconstruct the complex object wave in generalized phase-shifting interferometry (GPSI) without the iteration process and measurement of object wave intensity is proposed. This method can be used for GPSI of any frame number >or=2. Both computer simulations with smooth and diffusing object surfaces and optical experiments have verified the effectiveness of this method over a wide range of phase shifts with very satisfactory results.     

Quantitative phase retrieval in dynamic laser speckle interferometry

The rapid progress of modern manufacturing and inspection technologies has posed stringent requirements on optical techniques for vibration characterization and dynamic testing. Due to its simplicity, accuracy and whole-field characters, laser speckle interferometry has served as one of the major techniques for dynamic measurement. In this paper, a two-step phase shifting method is developed for quantitative speckle phase measurement, which helps to eliminate the specklegrams needed for phase evaluation and facilitate dynamic measurement. Unlike previously reported two-step methods using fringe patterns with known phase shift of π/2, a small unknown phase shift is employed instead in the proposed method, which eliminates the need for phase shifting devices. Further investigation shows that small phase shifts are preferable over large phase shifts in this method. Shearographic experiments conducted have demonstrated the effectiveness of the proposed technique.     

Dynamic interferometry and differential holography of irregular phase objects using phase conjugate reflection

By using phase conjugate reflection it should be possible to perform high-speed differential interferometry, that is, the measurement of small rapid changes in optical phase shift with time, as well as dynamic and/or differential holography, Schlieren, and other optical measurements of phase perturbations even on highly irregular transparent phase objects.     

Instantaneous quadrature components or Jones vector retrieval using the Pancharatnam-Berry phase in frequency domain low-coherence interferometry

We use the Pancharatnam-Berry phase as a multifunctional tool for low-coherence interferometry. This geometric phase shift enables instantaneous retrieval of the quadrature components of the complex interferometric signal. The phase shift is independent of wavelength and allows for a complex conjugate suppression of 40?dB for an optical bandwidth of 115?nm. Furthermore, this paper investigates the versatility of the geometric phase to perform polarization sensitive measurements. The Jones vector of the sample was obtained numerically, allowing sample birefringence and optical axis calculation.     

U-shaped optical fiber sensor based on multiple total internal reflections in heterodyne interferometry

In this paper, an optical fiber sensor based on multiple total internal reflections (MTIRs) in heterodyne interferometry is proposed. With the optical fiber sensor the phase shift difference due to the multiple total internal reflections effect between the p- and s-polarizations is measured by using heterodyne interferometry. Substituting the phase shift difference into Fresnel's equations, the refractive index for the tested medium can be calculated. The resolution of the sensor can reach 1.6×10^?6 refractive index unit (RIU). The optical fiber sensor could be valuable for chemical, biological and biochemical sensing. It has some merits, such as, high resolution and stability, high sensitivity, high resolution and real-time measurement.     

Carrier squeezing interferometry: suppressing phase errors from the inaccurate phase shift

The carrier squeezing interferometry algorithm is proposed to retrieve the phase from interferograms with phase shift errors. A linear carrier is introduced in the interferograms, and the image data is rearranged by the squeezing interferometry technology. In the spectrum of the rearranged image, the error lobe and the phase lobe are separated so the error-free phase can be retrieved by filtering. The simulated interferograms with phase shift errors are computed, and the precisions are better than 8.4×10(-4)λ. Its validation is verified by experiments, where a mean precision of 0.0040λ is obtained.     

Phase measurements in nonlinear optics

Measurement of the phase, and not only the intensity, of the nonlinear optical response of a system is important in many applications which are reviewed here. We demonstrate and compare several techniques for direct measurement of the phase of the nonlinear susceptibilities through nonlinear interferometry. Different ways of imparting a controllable phase shift are discussed. Unless the coherence length is impractically large, the preferred method is to use a variable-pressure gas cell to control the phase difference between the input laser pulse and the nonlinear optical signal.Prof. F. P. Schäfer on the occasion of his 65th birthday.     

相移干涉计量中相移器的同光路自动标定

基于相移干涉计量的基本原理，提出用相移ＥＳＰＩ光场的空间平均方法计算相位，不仅可实现相移干涉计量中相移器的同光路自动标定，而且还可以得到测量光场及所用相移器的计量特性．最后，将该标定方法所得相位值与等间距条纹相位标定值进行了比较，得到两者相对误差在可用电压区域内小于３％．     

Analysis of measuring features of interferometric methods for studying “weak” optical inhomogeneity with a small transverse size

Comparative analysis of interference methods, which are most promising for studying optical inhomogeneities with a small transverse size, is carried out. It is shown based on analysis of interference fringes for the two most widely used interferometric methods (two-beam interferometry with a reference wave and lateral-shear interferometry) that in the case of a lateral shift exceeding the geometrical size, lateral-shear interferometry shows twice as high sensitivity as that of double-beam interferometry with a reference wave and is more promising for estimating the size of “weak” optical inhomogeneities.     

PHASE SHIFT INTERFEROMETRY FOR ACCURATE TEMPERATURE MEASUREMENT AROUND A VAPOR BUBBLE

An interferometric measurement technique for determining accurately the temperature field around an axial symmetric vapor bubble that might be used for boiling investigations was developed. The specific setup of optical components and the fluid test cell for the generation of a single vapor bubble are described. The procedure and main steps to derive an accurate temperature field from the recorded interferograms are explained in detail. These are: wrapped phase calculation based on a four frames algorithm, phase unwrapping using Itoh algorithm, and Abe inversion for the calculation of the local temperatures. The results from interferometry are verified by point wise measurements using micro-thermocouples. Compared to formerly applied measurement techniques the presented phase shift interferometry leads to higher accuracy and higher spatial resolution.     

移相器微位移旋转误差的分析及测试

以压电陶瓷(PZT)微位移器为主要研究对象, 引入一种处理静态干涉图的新方法--虚光栅移相叠栅条纹法,设计实验对一台实际使用的移相器微位移旋转误差进行测试研究,对其引起的波面旋转情况进行了定量的计算分析,并给出测试结果.用虚光栅移相叠栅条纹法处理实验中加有载频的干涉图时,不需要使用任何移相器件,可以进行动态位相的检测,整个移相过程用计算机进行控制,避免了引入额外的移相误差.     

Single-shot kilohertz characterization of ultrashort pulses by spectral phase interferometry for direct electric-field reconstruction

We describe a method of characterizing ultrashort optical pulses that is based on the technique of spectral phase interferometry for direct electric-field reconstruction and is capable of simultaneously measuring the amplitude and the phase of the electric field of a sub-10-fs pulse at kilohertz acquisition rates on a single-shot basis. Use of this technique results in a dramatic increase (>50x) in acquisition rate compared with that of existing diagnostics for full E-field characterization and opens the door to a range of new experiments in which shot-to-shot phase and amplitude fluctuations are studied at kilohertz rates.     

Dual-wavelength laser source for onboard atom interferometry

We present a compact and stable dual-wavelength laser source for onboard atom interferometry with two different atomic species. It is based on frequency-doubled telecom lasers locked on a femtosecond optical frequency comb. We take advantage of the maturity of fiber telecom technology to reduce the number of free-space optical components, which are intrinsically less stable, and to make the setup immune to vibrations and thermal fluctuations. The source provides the frequency agility and phase stability required for atom interferometry and can easily be adapted to other cold atom experiments. We have shown its robustness by achieving the first dual-species K-Rb magneto-optical trap in microgravity during parabolic flights.     

Accurate phase-shifting digital interferometry

In phase-shifting interferometry experiments, the accuracy of the phase shift is a major issue. Many experimental and data analyses are done to cancel phase-shift errors inherent to the modulation techniques used. We propose to remove most of the phase-shift error by recourse to a frequency-shifting method. This approach can be applied to both holography and interferometry. We validate the idea with a holographic experiment.     

Surface Plasmon Polariton Fizeaus Dragging: via Relative Rotational Sensing

A new scheme focusing on the surface plasmon polariton interferometry between the metal and dielectric interface is introduced. The phase shift is measured by using surface plasmon polariton wave, generated at the interface of metallic and dielectric media. The phase shift of SPPs is modi?ed under phase and amplitude control of complex conductivity for interferometry. The control ?elds strongly in?uence the phase shift of SPPs for detection of molecular motion. The phase shift of SPPs is further modi?ed by Plasmon polariton Fizeaus dragging effect. We measure 20%–25%fractional change in delay and their phases shift between two left and right SPPs modes. Our results may have signi?cant applications in sensor interferometer technology.     

相移技术中五步等步长Stoilov算法的性能分析

Stoilov算法是近几年提出的一种五步等步长相移算法。有关文献中的误差分析表明 ,该算法的性能优于四步等步长Carr啨算法闹懈隽耍樱簦铮椋欤铮鏊惴ǖ恼繁泶锸?,采用线性误差理论详细分析了算法的性能 ,尤其是算法性能对相移步长的依赖关系。分析表明 ,可以选择一个最佳的相移步长以有效减少位相测量误差 :相移步长为 5 2°时可有效抑制二次相移量误差的影响 ;相移步长为 90°时可极大地减少光强误差的影响。最后给出了Stoilov算法与Carr啨算法和Hariharan算法的比较。     

Image encryption based on gyrator transform and two-step phase-shifting interferometry

A novel optical image encryption method is proposed, based on gyrator transform and phase-shifting interferometry. The input two-dimensional image to be encrypted is gyrator transformed two times, and two random phase masks are placed at the input plane and the output plane of the first gyrator transform. Two-step phase-shifting interferometry is used to record the digital holograms of the input image encrypted by use of double-random phase encoding technique in gyrator transform domain. The rotation angles of gyrator transform, the random phase mask in the gyrator plane and the arbitrary phase shift used for recording form the keys for decryption of the input image. Numerical simulations are presented to verify its validity and efficiency.     

基于菌紫质薄膜的相移器及其应用

设计了一种基于菌紫质光致各向异性的相移器,并把它用于相移干涉计量。取向随机分布的极性菌紫质分子对线偏振诱导光的选择性吸收导致分子取向分布不均匀,使其呈现宏观的各向异性,这种各向异性与诱导光的偏振特性密切相关,圆偏振光经过各向异性的菌紫质薄膜后,出射光的偏振特性完全由偏振诱导光决定。基于上述原理设计了一种新型的相移器,用琼斯矩阵法推导了基于相移器的相移干涉原理。该相移器在工作过程中不需要移动Mach-Zender干涉仪内部的任何器件,仅需要改变外部控制光路中诱导光的偏振取向就可以控制参考光的相位,有助于提高设备的抗振能力。用最小二乘法对相移干涉结果进行重建,得到了和实际相位一致的结果,验证了相移器的可行性。