18 November 2013 Fourier transform methods applied to an optical heterodyne profilometer
Author Affiliations +
Proceedings Volume 8785, 8th Iberoamerican Optics Meeting and 11th Latin American Meeting on Optics, Lasers, and Applications; 87853H (2013) https://doi.org/10.1117/12.2025887
Event: 8th Ibero American Optics Meeting/11th Latin American Meeting on Optics, Lasers, and Applications, 2013, Porto, Portugal
Abstract
In this work, theory and experiment describe the performance of a surface profile measurement device based on optical heterodyne interferometry are presented. The object and reference beams propagating through the interferometer are obtained by single-pass through an acousto-optic modulator. The diffraction orders 0 and the Doppler-shifted +1 (object and reference beams, respectively) are manipulated to propagate collinearly towards the interferometer output where a fast photodetector is placed to collect the irradiance. The modulated optical signal is Fourier transformed using a data acquisition card and RF communications software. The peak centered at the acousto-optic frequency in the power spectrum is filtered and averaged. The irregularities on the surface of the reflective sample are proportional to the height of this peak. The profile of a reflective blazed grating has been sketched by translating laterally the sample using a nanopositioning system. Experimental results are compared to the measurement done with a scanning electron microscope. There has been found a good agreement between both methods.
© (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
A. Beltrán-González, A. Beltrán-González, G. García-Torales, G. García-Torales, G. Martínez-Ponce, G. Martínez-Ponce, } "Fourier transform methods applied to an optical heterodyne profilometer", Proc. SPIE 8785, 8th Iberoamerican Optics Meeting and 11th Latin American Meeting on Optics, Lasers, and Applications, 87853H (18 November 2013); doi: 10.1117/12.2025887; https://doi.org/10.1117/12.2025887
PROCEEDINGS
6 PAGES


SHARE
RELATED CONTENT


Back to Top