一种新型干涉选择调幅光谱仪的研究

讨论一种新型干涉选择调幅光谱仪的光路设计，利用补偿板的扭动实现振幅调制。文章同时对幅射通量和分辨率进行了理论分析，采用矩形光栏时，分辨率为光栅分辨率的１．３５倍。文章还讨论了采用椭圆形光栏时，仪器函数曲线的切趾。     

Contrast reversal with a point-diffraction interferometer with a carrier frequency

A modified point diffraction interferometer is presented, where interference is made in the first diffracted order of a composite grating. A 180° phase shift between reference and object beam is introduced to obtain a complete image contrast reversal.     

改变写入Bragg波长的干涉条纹运动的扫描式Talbot干涉仪

一种干涉条纹运动的扫描式Talbot干涉仪被用于改变光纤Bragg光栅的写入Bragg波长。在系统中,光纤光栅是由来自相位掩模的±1级衍射光经平面镜反射后在远场形成紫外干涉条纹写入的,其中,相位掩模被用作±1级衍射光的分束器。值得注意的是通过干涉条纹的运动来扫描写入光纤光栅,有效降低了Talbot干涉仪对写入光源相干性的要求。     

Atom interferometers manipulated through the toroidal trap realized by the interference patterns of Laguerre-Gaussian beams

In this paper, we proposed new constructions of atom interferometers manipulated through the toroidal trap formed by the interference patterns of two co-propagation Laguerre-Gaussian (LG) beams. The coherent splitting and merging of the atomic ensemble, which is essential for the atom interferometer, is realized by the interference pattern of two LG beams. Along the beam propagation direction, a single-well trap is evolved into a double-well trap and then recombined back into a single-well trap, which can be used to form an atom interferometer.     

Variable Wavelengths Fiber Bragg Gratings Written with A Phase Mask and Four Prisms

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Phase profile analysis of transparent objects through the use of a two windows interferometer based on a one beam splitter configuration

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.     

Variable Wavelengths Fiber Bragg Gratings Written with A Phase Mask and Four Prisms

Using only one diffractive element, the Talbot interferometer provides a robust and inherently stable method for reproducing fiber Bragg gratings with variable wavelengths, and reduces the complexity of the fiber grating fabrication system. However, the usable length of the grating is limited by the practical length of the mirrors. This paper presents a phase mask with two fixed prisms and two rotational prisms to inscribe fiber Bragg gratings with variable Bragg wavelengths. In this system, the fiber Bragg grating is inscribed by UV interference stripes of 193 nm derived from two rotational prisms and two fixed prisms, where phase mask is used as a beam splitter of ±1 order diffraction light. It is noteworthy that the tunable phase mask interferometer decreases the demand of the length of prism evidently.     

Fourier optics analysis of grating sensors with tilt errors

Dynamic diffraction gratings can be microfabricated with precision and offer extremely sensitive displacement measurements and light intensity modulation. The effect of pure translation of the moving part of the grating on diffracted order intensities is well known. This study focuses on the parameters that limit the intensity and the contrast of the interference. The effects of grating duty cycle, mirror reflectivities, sensor tilt and detector size are investigated using Fourier optics theory and Gaussian beam optics. Analytical findings reveal that fringe visibility becomes <0.3 when the optical path variation exceeds half the wavelength within the grating interferometer. The fringe visibility can be compensated by monitoring the interfering portion of the diffracted order light only through detector size reduction in the expense of optical power. Experiments were conducted with a grating interferometer that resulted in an eightfold increase in fringe visibility with reduced detector size, which is in agreement with theory. Findings show that diffraction grating readout principle is not limited to translating sensors but also can be used for sensors with tilt or other deflection modes.     

Changing photo-written Bragg wavelengths of fiber gratings via one phase mask and four mirrors

A phase mask interferometer is developed to photo-write long gratings with arbitrary Bragg wavelengths. In this system, the fiber Bragg grating is photo-written by UV interference stripes of 193 nm reflected from two rotatable mirrors and two fixed mirrors, where the phase mask is not only used as a beam splitter, but also initialized the reference quantity of Bragg wavelength; the fixed mirrors are used for reducing the incident angle; the rotatable mirrors are used for adjusting the corresponding photo-written Bragg wavelength. It is worth noting that the photo-written length is fourfold as high as the length in the Talbot interferometer with the same mirror size.     

An X-ray interferometer with Bragg case beam splitting and beam recombination

A new type of X-ray interferometer which uses Bragg case transmission for beam splitting and for beam recombination is described. The principles and special problems of this interferometer are discussed and a strict plane-wave treatment of the interference phenomena is presented. The feasibility of such a device is demonstrated by some interference patterns, obtained with an instrument made from a silicon crystal for use with copperKα radiation and the 220 Bragg reflection. Since, for the operation of the Bragg case interferometer, strong absorption is not essential, such devices may also be more suitable than the previously reported Laue case interferometer^1,2 for use with neutrons.     

点衍射干涉检测技术

本文介绍了点衍射干涉仪不同发展阶段的特点和应用。点衍射干涉仪由波长量级的针孔产生高质量的球面波作为参考波前,能够得到衍射极限性能的分辨率。按照不同的光路特点,点衍射干涉仪可分为点衍射共路干涉和点衍射非共路干涉两种结构,主要应用于高精度波前检测和面形检测。共路干涉结构简单紧凑,对环境振动不敏感,对光源相干度要求不高,可利用光束偏振态及光栅衍射分束的特性对传统点衍射板进行改造,在全共路点衍射干涉仪中引入时间相位调制技术和干涉对比度可调技术,可进一步提高波前检测精度。采用反射式针孔和各种光纤结构发展了非共路点衍射干涉仪,实现了大口径、高精度球面反射镜面形的测量。本文重点阐述了用于极紫外光刻投影物镜中高精度球面反射镜面形检测的反射式针孔点衍射干涉仪,并展望了点衍射检测技术在生物检测等领域的应用前景和发展趋势。     

New experimental results on the interference of the states of the hydrogen atom due to long-range interaction with the metal surface

The interference of the 2P state of the hydrogen atom due to unknown long-range interaction with the metal surface (Sokolov effect) has been studied by an atomic interferometer. In contrast to previous experiments, where an atomic beam passed through slits in metal plates, a beam in the presented experiments passes at a given distance from the edges of the plates. It has been found that the interference is clearly observed if two plates are located on the same side of the beam. However, this interference disappears if one plate is displaced to the opposite side. This result cannot be explained in the framework of the available hypotheses on the nature of the effect under investigation.     

利用一块相位掩模和两块棱镜改变光纤光栅的写入Bragg波长

一种相位掩模干涉仪被用于写入不同的Bragg波长的。在该系统中,光纤光栅是由来自两可旋转棱镜所形成的紫外干涉条纹写入的,其中,相位掩模被用作&;#61617;1级衍射光的分束器。并且,当两块顶角由相位掩模的&;#61617;1级衍射角和棱镜折射率确定的棱镜的底部相互平行放置时,该相位掩模给出了Bragg波长的参考值。当Bragg波长的移位为1 nm时,棱镜最大的旋转角为1 degree,最小的旋转角是~2.4 minute。与Talbot干涉仪中平面镜的旋转角~23 second/nm相比,该相位干涉仪中棱镜的旋转精度降低了2~3个数量级。替代了许多具有不同光栅周期的相位掩模,该可调谐相位掩模干涉仪仅用一块相位掩模和两块旋转棱镜就实现了写入具有不同Bragg波长的光栅。     

Symmetric Talbot bands experiment

By impinging a step phase-shifted white light beam on a grating-based interferometer, one of diffraction orders is modulated and interference bands so-called “Talbot bands” are formed. Here, classical Talbot bands set up is generalized to the symmetry configuration, in which two glass plates of the same thickness instead of one plate, are inserted halfway into the grating interferometer aperture. Formation of Talbot bands were studied theoretically and experimentally. Frequency impulse response of the new Talbot bands setup was, also presented. It was demonstrated that symmetric set-up causes modulation of both of two opposite orders, according to the theory. In this manner, their visibility is the same. As a result, this similarity of the visibility is reduced while the symmetric arrangement of the glass plates with respect to the optical axis, is broken.     

Polarization Sagnac interferometer with a reflective grating beam splitter

All-reflective interferometric gravitational-wave detector configurations with a diffraction grating as a power beam splitter have been proposed to reduce thermal lensing. We demonstrate the use of a diffraction grating as a polarization beam splitter in a zero-area polarization Sagnac interferometer.     

软X射线双频光栅剪切干涉法研究

本文中设计了一种利用软X射线双频光栅作为剪切干涉元件的剪切系统, 使剪切干涉法在软X射线波段得到了应用. 介绍了软X射线双频光栅的结构及衍射特性, 在同步辐射光束线对双频光栅的效率分布进行了测试实验, 两个剪切级次的效率比值高于75%, 干扰级次效率低于5%. 利用软X射线双频光栅为剪切干涉光学元件, 对待测靶进行了静态检测, 得到了对比度高, 稳定的干涉条纹, 验证了该方法在软X射线等离子体密度诊断中的可行性. 关键词： 双频光栅 剪切干涉仪 软X射线 等离子体诊断     

Grating Interferometer Using ± 1st Order Beams for Step-Profile Altitude Difference Measurement

We propose a grating interferometer for step-profile altitude difference measurement. There are two main characteristics in this interferometer. The first is that the intensity distribution of the interference pattern is independent of the wavelength of the laser-diode used. No change of the intensity distribution occurs when the wavelength fluctuates. The second is that the measuring range is much larger than the wavelength of the light source because the spatial period of the grating is much larger than the wavelength. Sinusoidal phase modulating interferometry is easily applied to detect the phase variation of the interference pattern by vibrating the grating sinusoidally. The thickness of a 3.5-inch disk is measured with an accuracy of less than 0.5 μm.     

Theory of Atom Optics: Feynman’s Path Integral Approach

The present theory of atom optics is established mainly on the Schrödinger equations or the matrix mechanics equation. The authors present a new theoretical formulation of atom optics: Feynman’s path integral theory. Its advantage is that one can describe the diffraction and interference of atoms passing through slits (or grating), apertures, and standing wave laser field in Earth’s gravitational field by using a type of wave function and calculation is simple. For this reason, we derive the wave functions of particles in the following configurations: single slit (and slit with the van der Waals interaction), double slit, N slit, rectangular aperture, circular aperture, the Mach-Zehnder-type interferometer, the interferometer with the Raman beams, the Sagnac effect, the Aharonov-Casher effect, the Kapitza-Dirac diffraction effect, and the Aharonov-Bohm effect. The authors give a wave function of the state of particles on the screen in abovementioned configurations. Our formulas show good agreement with present experimental measurements.     

Diffractive beam splitter characterization via a power-recycled interferometer

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.     

All-fiber Mach-Zehnder curvature sensor based on multimode interference combined with a long-period grating

A novel Mach-Zehnder interferometer based on a fiber multimode interference structure combined with a long-period fiber grating (LPG) is proposed. The multimode interference is achieved through the use of a MMF section spliced between two single-mode fibers, with a length adjusted to couple a fraction of light into the cladding modes. A LPG placed after the MMF couples light back into the fiber core, completing the Mach-Zehnder interferometer. This novel configuration was demonstrated as a bending sensor.