A method of second harmonic measuring glass thickness with ultra-precision based on multi-beam laser heterodyne

Author

Wang, Chun Hui ; Li, Yan Chao ; Gao, Long ; Pang, Ya Jun

Author_Institution

Nat. Key Lab. of Tunable Laser Technol., Harbin Inst. of Technol., Harbin, China

fYear

2011

fDate

12-16 Oct. 2011

Firstpage

236

Lastpage

239

Abstract

This paper puts forwards a novel method of second harmonic of multi-beam laser heterodyne measurement for the thickness of the glass, which is based on the combination of Doppler effect and heterodyne technology, loaded the information of the thickness to the frequency difference of the multi-beam laser heterodyne signal by frequency modulation of the oscillating mirror, which is in the light path. Heterodyne signal frequency can be obtained by fast Fourier transform, and can obtain values of the thickness accurately after the multi-beam laser heterodyne signal demodulation. This method is used for simulate values of different thickness of the glass through numerical simulation of MATLAB and the obtained result shows that maximal relative error is less than 0.02%.

Keywords

Doppler effect; Fourier transform optics; demodulation; fast Fourier transforms; frequency modulation; glass; heterodyne detection; laser mirrors; mathematics computing; measurement by laser beam; numerical analysis; optical harmonic generation; optical information processing; optical modulation; optical signal detection; physics computing; thickness measurement; Doppler effect; MATLAB; SiO₂; fast Fourier transform; frequency modulation; glass thickness measurement; heterodyne signal demodulation; multibeam laser heterodyne; numerical simulation; oscillating mirror; second harmonic; Frequency measurement; Glass; Harmonic analysis; Laser beams; Measurement by laser beam; Mirrors; Thickness measurement; Fourier analysis; Heterodyne; Nondestructive testing;

fLanguage

English

Publisher

ieee

Conference_Titel

Optoelectronics and Microelectronics Technology (AISOMT), 2011 Academic International Symposium on

Conference_Location

Harbin

Print_ISBN

978-1-4577-0794-0

Type

conf

DOI

10.1109/AISMOT.2011.6159362

Filename

6159362