公开(公告)号：US20030112444A1

公开(公告)日：2003-06-19

申请号：US10024455

申请日：2001-12-18

Applicant: Massachusetts Institute of Technology

Inventor： Changhuei Yang ,  Adam Wax ,  Ramachandra R. Dasari ,  Michael S. Feld

IPC: G01B009/02

CPC classification number: G01B9/02007 ,  G01B9/02002 ,  G01B9/02078 ,  G01B9/0209 ,  G01B2290/45 ,  G01J9/04 ,  G01N21/45

Abstract: The methods of the present invention are directed at an accurate phase-based technique for measuring arbitrarily long optical distances with sub-nanometer precision. A preferred embodiment of the present invention method employs a interferometer, for example, a Michelson interferometer, with a pair of harmonically related light sources, one continuous wave (CW) and a second source having low coherence. By slightly adjusting the center wavelength of the low coherence source between scans of the target sample, the phase relationship between the heterodyne signals of the CW and low coherence light is used to measure the separation between reflecting interfaces with sub-nanometer precision. As the preferred embodiment of this method is completely free of 2null ambiguity, an issue that plagues most phase-based techniques, it can be used to measure arbitrarily long optical distances without loss of precision.

Abstract translation: 本发明的方法涉及用于以亚纳米精度测量任意长的光学距离的精确的基于相位的技术。 本发明方法的优选实施例采用干涉仪，例如迈克尔逊干涉仪，具有一对谐波相关的光源，一个连续波（CW）和具有低相干性的第二源。 通过在目标样本的扫描之间稍微调整低相干光源的中心波长，使用CW的外差信号与低相干光之间的相位关系来测量具有亚纳米精度的反射界面之间的距离。 由于该方法的优选实施例完全不存在2pi模糊度，这是一种困扰大多数基于相位的技术的问题，可以用于测量任意长的光学距离而不损失精度。