TWO-WAVELENGTH INTERFEROMETRY WITH OPTICAL HETERODYNE PROCESS
    3.
    发明申请
    TWO-WAVELENGTH INTERFEROMETRY WITH OPTICAL HETERODYNE PROCESS 审中-公开
    具有光学异质性过程的双波长干涉

    公开(公告)号:WO1988008519A1

    公开(公告)日:1988-11-03

    申请号:PCT/CH1988000070

    申请日:1988-03-30

    Abstract: The device comprises : a laser device (10, 20) for the frequency n1 (11) and the frequency n2 (21), each provided with a polarizing beam splitter (12, 22) for producing crossed polarized partial beams of frequency n1 (13, 14) and n2 (23, 24), respectively, with a modulator (18, 28) for shifting the frequency of each of the partial beams to the frequency f1 or f2, respectively, with a pair of deflecting mirrors (15, 17, 25, 27) and with a polarizing beam splitter (16, 26) for uniting (19, 29) the partial beams n1, n1+f1, n2, n2+f2; two photodetectors (35, 45) before each of which a polarizer (34, 44) is arranged; a Michelson interferometer; a non-polarizing beam splitter (30) for distributing each of the partial beams (19, 29) into a measurement light beam (32) or a reference light beam (33). The reference light beam is transmitted to the corresponding photodetector (35). The measurement light beam (32) is transmitted to the Michelson interferometer and then to the corresponding photodetector (45).The photodetector signals are modulated in function of the amplitude, and the phase difference between the two modulated signals is determined. This phase difference depends only on the position of the test object and the equivalent wavelenght of the difference, n1-n2. For stabilization or correction, the device can be executed in duplicate and one of the executions used as a reference. The corresponding process can be applied to determine positions or distances as the interval between two positions. Uncertainties can be eliminated by shifting the distance or changing the frequency with simultaneous integration of the phase difference over time.

    Abstract translation: 该装置包括:用于频率n1(11)和频率n2(21)的激光装置(10,20),每个激光装置(10,20)设有偏振分束器(12,22),用于产生频率为n1的十字偏振分光束 ,14)和n2(23,24)分别具有用于将每个分光束的频率分别用一对偏转镜(15,17)移动到频率f1或f2的调制器(18,28) (25,27),以及用于将部分光束n1,n1 + f1,n2,n2 + f2联合(​​19,29)的偏振分束器(16,26) 在每个光电检测器(35,45)之前布置有偏振器(34,44); 迈克尔逊干涉仪 用于将每个分光束(19,29)分配到测量光束(32)或参考光束(33)中的非偏振分束器(30)。 参考光束被传送到相应的光电检测器(35)。 将测量光束(32)传输到迈克尔逊干涉仪,然后传输到相应的光电检测器(45)。光电探测器信号由幅度调制,两个调制信号之间的相位差被确定。 该相位差仅取决于测试对象的位置和差值的等效波长n1-n2。 对于稳定或校正,设备可以重复执行,其中一个执行作为参考。 可以应用相应的过程来确定位置或距离作为两个位置之间的间隔。 通过移动距离或改变频率可以消除不确定性,同时整合相位差随时间的变化。

    Heterodyne interferometer system
    5.
    发明公开
    Heterodyne interferometer system 失效
    HETERODYNE干扰仪系统

    公开(公告)号:EP0194941A3

    公开(公告)日:1988-06-08

    申请号:EP86400506

    申请日:1986-03-11

    Abstract: A heterodyne interferometer system utilizes a single stabilized frequency linearly polarized laser input beam (18) from a light source (10) which is provided to an acousto-optic device (20) along with a frequency stabilized electrical reference signal (32) from an oscillator (30) for transforming the input beam (18) into a pair of orthogonally polarized beams (40,50) differing in frequency by the reference signal frequency prior to providing these beams (40,50) to a polarization type interferometer (70). A mixing polarizer (60) mixes the beams (46,56) after they traverse the interferometer (70) and provides the mixed beams (62,64) to a photoelectric detector (65) where they are utilized to produce an electrical measurement signal (66). This electrical measurement signal (66) is processed in a phase meter/accumulator (68) along with the reference signal (32) to produce an output signal (80) which is the sum of phase difference on a cycle-by-cycle basis between the measurement signal (66) and the reference signal (32). The phase meter/accumulator (68) includes an analog-to-digital converter and a memory register for the previous cycle, with the measurement resolution being determined by the number of bits of the analog-to-digital converter.

    Method of and device for realtime measurement of the state of polarization of a quasi-monochromatic light beam
    6.
    发明公开
    Method of and device for realtime measurement of the state of polarization of a quasi-monochromatic light beam 失效
    用于实时测量准单色光束偏振状态的方法和装置

    公开(公告)号:EP0172568A3

    公开(公告)日:1987-09-02

    申请号:EP85110477

    申请日:1985-08-21

    CPC classification number: G01J4/00 G01J9/04

    Abstract: The method and the device are based on interference techniques. Two quasi-monochromatic radiations (2a, 2b; 102a, 102b; 202a, 202b) with slightly different optical frequencies are generated. A radiation is converted into a 45° linearly-polarized radiation, while the other presents the polarization state imposed by a body under test (4, 204). In each radiation, horizontal and vertical polarization components are separated, and then recombined into two different beams (20a, 21a; 34, 35) comprising radiations at both frequencies, respectively polarized in the same plane. Beatings between the two components of each beam are originated and from the two electrical signals in the radio frequency range thus obtained the information is extracted on the relative phase and the amplitude of the two components of the radiation with polarization imposed by the body under test (4, 204).

    Active mirror wavefront sensor
    7.
    发明公开
    Active mirror wavefront sensor 失效
    主动镜面波形传感器

    公开(公告)号:EP0158505A3

    公开(公告)日:1985-11-21

    申请号:EP85302338

    申请日:1985-04-03

    Applicant: TRW INC.

    CPC classification number: G01J9/02

    Abstract: An interferometer, and corresponding method, for use in the measurement and correction of wavefront aberrations in a beam of radiation. The interferometer includes optical elements for generating a reference beam with a known wavefront phase characteristic. The reference beam is recombined with the sample beam, to produce an interference pattern indicative of the phase aberrations in the sample beam as compared with the reference beam. An array of detectors produces electrical signals corresponding to discrete elements of the detected pattern, and an electrical circuit for each elemental detector generates phase correction signals to be applied to a set of movable mirror elements arranged to effect phase changes in the sample beam path. The movable mirror elements adjust the elemental path lengths of the sample beam to yield zero detected phase differences. The mirror elements may be integrated into the interferometer, or may take the form of a deformable mirror used for phase compensation of a light beam. The reference beam in the preferred form of the invention is dithered at a high frequency to minimize the effect of noise, and each electrical circuit includes a synchronous detector to remove the dither-frequency component. In accordance with one disclosed form of the invention, the reference beam is not planar but is aberrated in a conjugate relationship with the radiation beam to be corrected, to provide improved control loop performance.

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