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1.
Based on the modification of a point diffraction interferometer, a method for measuring the optical fields from remote objects and external sources is developed. In this method, the reference beam is obtained from the studied beam by filtration of its spatial spectrum with a single-mode optical fiber. To eliminate the effect of phase errors caused by the nonideality of elements of the optical scheme on the measurement results, we developed a procedure of interferometer calibration that permits one to determine these errors with the aim of subtracting them from the measured field phase distributions. 相似文献
2.
Christopher Middlebrook Michael Roggemann Glenn Boreman Nikola Subotic Kyle Cooper William Buller Weidong Yang Javier Alda 《International Journal of Infrared and Millimeter Waves》2008,29(2):179-187
The first direct measurement of the mutual coherence function of a spatially incoherent infrared beam was performed at 10.6 μm
using a pair of infrared dipole nano-wire antennas that were connected to a common bolometer in the center of the pair by
short lengths of coplanar strip transmission line. A spatially incoherent source was constructed by dithering a BaF2 diffuser
near the focus of a CO2 laser beam. The distance from the diffuser to the nano-wire antenna pair was held constant while the
distance from the focus of the laser beam to the diffuser was varied to control the effective diameter of the source. The
measured bolometer signal was proportional to the magnitude of the mutual coherence function at the plane of the antennas.
The experimental results were found to match the predicted performance closely. If this technology can be extended to large
arrays, a form of synthetic aperture optical imaging based on the Van Cittert-Zernike theorem is possible, similar to that
performed at microwave frequencies now by astronomers. This has the potential to greatly increase the angular resolution attainable
with optical instruments. 相似文献
3.
The effect of acoustooptic (AO) Bragg diffraction on the degree of spatial coherence of an optical beam formed as the result of transmission of a Gaussian beam through a diffuser is studied. Experiments performed on the basis of the AO Bragg interaction in a single crystal of TeO2 confirmed that the optical beam areas characterized by a higher spatial coherence diffract with a considerably higher efficiency than the low-coherence areas. In addition, the character of the speckle-structure distribution of the optical field of the diffracted beam is practically isotropic. 相似文献
4.
以无缓冲气化学氧碘激光器(COIL)实验器件的数据计算得到的混合喷管出口参数平均值作为光腔入口条件,对6种不同构型的扩压器从光腔入口至扩压器出口的流场进行了数值模拟,得出了各流场参数分布;对不同构型扩压器的流场特点、总压恢复性能进行了分析;研究了扩压器出口背压对流场参数的影响。结果表明:对于主流无缓冲气的COIL,等截面扩压器具有较好的压力恢复性能;增大扩压器出口背压可以使扩压器的压力恢复性能提高,然而,较高的背压使激波串向光腔方向移动,从而使光腔流场受到干扰,影响光腔的光束质量。 相似文献
5.
U. Sterr K. Sengstock J. H. Müller D. Bettermann W. Ertmer 《Applied physics. B, Lasers and optics》1992,54(5):341-346
In this paper it will be shown that an atom interferometer, based on the coherent splitting of the atomic wavefunction by four travelling waves (Ramsey interferometer), may be explained by a purely mechanical interpretation. As our first application of this Ramsey interferometer we have measured the phase shifts respectively optical length changes in a magnesium atomic beam caused by the acceleration of the partial atomic wave in one arm of the interferometer. This acceleration was achieved by the dipole force exerted by an off-resonant crossing laser beam which interacted with the ground state part of the wavefunction only. Further applications of this interferometer and improvements due to laser cooling will be discussed. 相似文献
6.
A grating interferometer composed of two transmission gratings in tandem irradiated incoherently was studied for an atom interferometer. Determination of its interference effect was made with consideration of the optical transfer function. An atom beam had a velocity distribution, which made the influence on the interference phenomenon. The calculated results show that the fringe (grating image) with relatively high contrast is obtained under a certain grating arrangement even if the interferometer is irradiated by a spatially incoherent polychromatic atom beam. 相似文献
7.
Friedrich D Burmeister O Bunkowski A Clausnitzer T Fahr S Kley EB Tünnermann A Danzmann K Schnabel R 《Optics letters》2008,33(2):101-103
We used the high-precision laser interferometer technique of power recycling to characterize the optical loss of an all-reflective grating beam splitter. This beam splitter was used to set up a Michelson interferometer with a power-recycling resonator with a finesse of 883. Analyzing the results obtained, we determined the beam splitter's total optical loss to be (0.193+/-0.019)%. Low loss all-reflective beam splitters might find application in future high-power laser interferometers for the detection of gravitational waves. 相似文献
8.
9.
Leibfried D DeMarco B Meyer V Rowe M Ben-Kish A Britton J Itano WM Jelenković B Langer C Rosenband T Wineland DJ 《Physical review letters》2002,89(24):247901
We show how an experimentally realized set of operations on a single trapped ion is sufficient to simulate a wide class of Hamiltonians of a spin-1/2 particle in an external potential. This system is also able to simulate other physical dynamics. As a demonstration, we simulate the action of two nth order nonlinear optical beam splitters comprising an interferometer sensitive to phase shift in one of the interferometer beam paths. The sensitivity in determining these phase shifts increases linearly with n, and the simulation demonstrates that the use of nonlinear beam splitters (n=2,3) enhances this sensitivity compared to the standard quantum limit imposed by a linear beam splitter (n=1). 相似文献
10.
A technique is presented for determining the frequency modulation transfer function of a laser. The method is based on a Mach–Zehnder interferometer, with a significant difference in the optical path lengths of the two arms. A frequency-modulated laser beam incident on the interferometer produces a phase-modulated photocurrent signal with an effective modulation index that is related to the amplitude of the optical frequency modulation. Techniques for determining both the amplitude and the phase of the optical frequency modulation from the photocurrent signal are described. 相似文献
11.
介绍了光纤Mach-Zehnder(MZ)干涉仪系统的结构.给出了光纤Mach-Zehnder干涉仪系统中信号光与参考光的干涉原理以及影响干涉光强的因素.同时也分析了光纤耦合器的交叉耦合,另外也给出了PZT的作用.阐述了光纤偏振控制器的结构、工作原理及其对光纤Mach-Zehnder干涉仪系统传感臂偏振态的控制,最后给出了光纤Mach-Zehnder干涉仪系统的应用. 相似文献
12.
用紫外激光在氢载、高掺锗光纤中激起强烈的折射率扰动,形成菲涅耳反射器,制成了本征光纤双束干涉仪,并用温敏实验证明了这种菲涅耳反射器的存在,表明这种干涉仪可以用作传感器. 相似文献
13.
14.
Nuster R Gruen H Reitinger B Burgholzer P Gratt S Passler K Paltauf G 《Optics letters》2011,36(6):981-983
An optical detection setup consisting of a focused laser beam fed into a downstream Fabry-Perot interferometer (FPI) for demodulation of acoustically generated optical phase variations is investigated for its applicability in photoacoustic tomography. The device measures the time derivative of acoustic signals integrated along the beam. Compared to a setup where the detection beam is part of a Mach-Zehnder interferometer, the signal-to-noise ratio of the FPI is lower, but the image quality of the two devices is similar. Using the FPI in a photoacoustic tomograph allows scanning the probe beam around the imaging object without moving the latter. 相似文献
15.
A new beam deflection technique is based on modulating the optical transmission characteristics of a modified Fabry-Perot interferometer. Electro-optically changing the interferometer length leads to fast high resolution scanning of the transmission fringe. Experiments have been conducted using the 4880 Å argon laser line with an interferometer containing a LiNbO3 crystal. 相似文献
16.
New multiplexed system for synchronous measurement of out-of-plane deformation and two orthogonal slopes
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Yonghong Wang 《中国物理 B》2022,31(3):34202-034202
We propose a novel system for synchronous measurement of out-of-plane deformation and two orthogonal slopes using a single camera. The linearly polarized reference beam introduced by an optical fiber interferes with the unpolarized object beam to measure the out-of-plane deformation. A modified Mach—Zehnder interferometer is used to measure the two orthogonal slopes of the out-of-plane deformation. One of the object beams of the Mach—Zehnder interferometer is an unpolarized beam, and the other object beam is split into two orthogonal linearly polarized object beams by a polarizing prism. The two beams are orthogonally polarized. Hence, they will not interfere with each other. The two polarized beams respectively interfere with the unpolarized beam to simultaneously measure the two orthogonal slopes of the out-of-plane deformation. In addition, the imaging lens and apertures are respectively placed in three optical paths to independently control the carrier frequencies and shearing amounts. The effectiveness of this method can be proved by measuring two pressure-loaded circular plates. 相似文献
17.
《Optik》2014,125(24):7227-7230
In this research we implemented a two windows interferometer based on polarization phase shifting and grating interferometry techniques in order to retrieve the phase data profile of the object in a single capture. The optical configuration has two optical beams with circular polarization in opposite directions, and it is coupled with a 4-f system. An amplitude grid is used as a filter which is placed at the Fourier plane to obtain replicas of each beam which can properly interfere, depending on the separation between beams. The interferometer presents the capability of changing the beam separation in order to make different orders interfere properly. The interference patterns produced can be separately modulated through the operation of linear polarizer's placed on each interference replica. In order to present the capabilities of the system we will select four interferograms result of contiguous orders interference. 相似文献
18.
A dual interferometric displacement measurement system is presented where a Wollaston prism interferometer is employed in conjunction with a normal Michelson interferometer. The system operates without the use of external polarizers, apart from those associated with the Wollaston prism interferometer itself. It is shown that an optical path difference induced in the Michelson interferometer can be detected using the Wollaston prism in a normal interferometer arrangement. Further, the interference pattern produced by the Wollaston prism interferometer changes in a measurable, linear fashion as the optical path difference from the Michelson interferometer alters. A simple theoretical analysis of the system is presented and used to derive a computer model of the optical arrangement. Results from an experimental implementation of the system, using a Wollaston prism with a beam separation of 0.5 degrees and a superluminescent diode, of wavelength 825 nm, as a light source, are included and compared to the results from the computer model. 相似文献
19.
Kaye S. Morgan Sarah C. Irvine Yoshio Suzuki Akihisa Takeuchi Karen K.W. Siu 《Optics Communications》2010,283(2):216-19789
A suitably large coherence area is important in coherent X-ray optics, when using techniques such as interferometry or phase contrast imaging (PCI). The work done by Suzuki using a prism interferometer to measure X-ray coherence at 12.4 keV [1] is here extended to consider the use of a diffuser at the bio-medical imaging energy of 25 keV. In order to achieve a broader, more even X-ray field and eliminate speckle, a spinning piece of paper may be used as a rotating random-phase screen to diffuse the hard X-ray beam, but this will concomitantly decrease the magnitude of the complex degree of second-order coherence. We also study the effect of source size and source-to-sample distance on coherence, where imaging area and required flux must be considered. Coherence measurements at the 20XU beamline at the SPring-8 synchrotron are compared to results from wave-optical computer modelling. These show that while the diffuser will decrease the magnitude of the complex degree of coherence, further free-space propagation will lessen this effect. In the design of an experiment, the collimating slit size and use of a diffuser must therefore be balanced with distance from the source, in order to maximise coherence while maintaining the desired field of view and exposure time. 相似文献