Two-dimensional displacement measurement by quasi-common-optical-path heterodyne grating interferometer

Heterodyne common-path grating interferometer with Littrow configuration.

This paper presents a heterodyne common-path grating interferometer with Littrow configuration (HCGIL). The HCGIL can effectively overcome environmental disturbance effect and the DC offset and the amplitude variation of the measurement signals. Experimental results match well with the HP5529A results for long-range measurements. Results also show that the estimated measurement resolution is 0....

Subnanometer Displacement Measurement Using Common-path Grating Interferometry

Improved common-path optical heterodyne interferometer for measuring small optical rotation angle of chiral medium

An improved common-path optical heterodyne interferometry for measuring small optical rotation angle of chiral liquid is presented. The optical rotation angle can be determined by the phase difference between the test and reference signals. By means of inserting a phase retarder behind the test sample, the measuring resolution of optical rotation angle is greatly enhanced. The theoretical predi...

Space position measurement using long-path heterodyne interferometer with optical frequency comb.

A heterodyne interference system was developed for position measurement. A stabilized optical-frequency comb is used as the laser source. The preliminary experiment to measure a distance of 22.478 m shows a drift of 1.6 μm in 20 minutes after the temperature compensation. Comparison and frequency shift experiments have been done for a distance of about 7.493 m. The experimental results show tha...

Heterodyne displacement interferometer, insensitive for input polarization.

Periodic nonlinearity (PNL) in displacement interferometers is a systematic error source that limits measurement accuracy. The PNL of coaxial heterodyne interferometers is highly influenced by the polarization state and orientation of the source frequencies. In this Letter, we investigate this error source and discuss two interferometer designs, designed at TU Delft, that showed very low levels...