Papers by Keyword: Common-Path

Abstract: A new, common-path, in-axis concentric beam-splitting Michelson interferometer is demonstrated for optical coherence tomography (OCT), which can be used to perform high-resolution cross-sectional in vivo and in situ imaging of biological tissues. A piece of glass tube with its inner diameter smaller than the beam-width of the collimated light is used to split the light into a reference and sample beam. In order to obtain the optimal spectral interferogram of this OCT system, an infrared optical path adjustment method was introduced in this paper.

Abstract: In this paper, we report a novel quasi-common-path laser feedback interferometer (QLFI) for highly stable, high-resolution and non-contact displacement measurement. QLFI measures the displacement of the target by measuring the phase of feedback light. In addition to the target-generated feedback light (frequency shifted by 2#), a reference mirror generates a reference feedback light which is frequency shifted by #. The phase variations of both feedback lights are measured by heterodyne detection simultaneously and their difference offers the phase variations caused only by target displacement. When the optical path lengths of the reference and measuring feedback light are nearly the same, the phase fluctuations caused by the environment and laser instability are effectively removed. The heat-induced deformation of a He-Ne laser tube is successfully in-line measured using QLFI.