We present experimental results on the output power stabilization of an Ar⁺ laser for a direct circular laser writing system (CLWS). Instability of the laser output power in the CLWS causes resolution fluctuations of being fabricated diffractive optical elements or computer-generated holograms. For the purpose of reducing the power fluctuations, we have constituted a feedback loop with an acousto-optic modulator, a photodetector, and a servo controller. Here very important things are proper conception of the servo controller and selection of a proper photodetector depending on what kinds of lasers to be controlled. In this system, we have achieved the stability of ± 0.20 % for 12 minutes and the relative intensity noise level of 2.1 x 10^-7 Hz^-1/2 at 100 Hz. In addition, we applied our system to a 2 mW internal mirror He-Ne laser. As a consequence, we achieved the output power stability of ± 0.12 % for 25 minutes.

Date Published: 17 January 2008
PDF: 7 pages
Proc. SPIE 6723, 3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, 672357 (17 January 2008); doi: 10.1117/12.783746

Published in SPIE Proceedings Vol. 6723:
3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment
Junhua Pan; James C. Wyant; Hexin Wang, Editor(s)