Heterodyne interferometer for measurement of in-plane displacement with subnanometer resolution

Abstract

A novel method of the measurement of in-plane displacement is presented. This method includes a heterodyne light source, a moving grating and a lock-in amplifier for phase measurement. The phase variation which resulted from the grating movement is measured by an optical heterodyne interferometer. The short and long displacement can be measured by our method. The theoretical resolution is about 1 pm. If considering the high frequency noise, the measurement error or resolution is about 0.2 nm yet.

A high-resolution displacement sensor based on a grating interferometer with the phase modulation technique

“…By employing PMT, the displacement sensitivity is increased from 7 to 19.8 mV nm −1 and the displacement resolution is also increased from 1.7 to 0.05 nm. The displacement resolutions of [1] and [2] are 0.31 and 0.2 nm, respectively. Therefore, the proposed displacement sensor provides much better resolution and broad dynamic range, which is very helpful for precision measurements.…”

“…Displacement exactly corresponds to the optical fringe changes and the optical path difference of the interferometer; therefore, the measurement of displacement is the most basic application of the interferometer. Over the past few decades, displacement detection based on grating interferometers has been used for displacement measurement or other quantities which can be converted to displacement [1][2][3][4][5][6][7], because they offer high resolution and good stability under changing ambient air. Demarest [1] and Lee [2] proposed heterodyne interferometers for displacement measurement with resolutions of 0.3 and 0.2 nm, respectively.…”

“…Over the past few decades, displacement detection based on grating interferometers has been used for displacement measurement or other quantities which can be converted to displacement [1][2][3][4][5][6][7], because they offer high resolution and good stability under changing ambient air. Demarest [1] and Lee [2] proposed heterodyne interferometers for displacement measurement with resolutions of 0.3 and 0.2 nm, respectively. Displacement measurement based on a homodyne polarization interferometer with 0.5 nm resolution was demonstrated by Liu et al [4].…”

Optical accelerometer based on grating interferometer with phase modulation technique

“…In the past few decades grating interferometers have been used for displacement measurement or other quantities, which can be inverted to displacement [13][14][15][16][17][18][19] because they offer high resolution and good stability under changing ambient air. In a previous paper, we have proposed a displacement sensor based on grating interferometer with nanometer-scale displacement resolution [20].…”