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Proceedings Paper

Reflectivity measurement with optical feedback cavity ring-down technique employing a multi-longitudinal-mode diode laser
Author(s): Zhechao Qu; Yanling Han; Shengming Xiong; Bincheng Li
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Paper Abstract

Cavity ring-down (CRD) techniques based on measuring the rate of decay of light intensity inside the optical cavity, are widely used for trace gas analysis and high reflectivity measurement. In this presentation a filtered optical feedback CRD (FOF-CRD) technique employing a multi-longitudinal-mode continuous-wave diode laser is investigated for measuring high reflectivity of high reflective mirrors. The original spectrum of the diode laser without the effect of FOF has two longitudinal modes covering tens of the free spectral ranges (FSR) of the ring down cavity (RDC). Due to the relatively broadband spectrum, the theoretical efficiency of coupling the laser power into the RDC is less than 0.05%. In the FOF-CRD scheme, on the other hand, the FOF induced overall spectrum broadening is experimentally observed, with the diode laser running with several longitudinal modes. However the bandwidth of each longitudinal mode is significantly reduced. The coupling efficiency of the laser power into the RDC is higher than 20% in FOF-CRD technique. The enhancement of the coupling efficiency induced by the FOF effect is nearly three orders of magnitude. High accuracy measurements of high reflectivity are achieved with this simple FOF-CRD scheme.

Paper Details

Date Published: 28 November 2011
PDF: 8 pages
Proc. SPIE 8190, Laser-Induced Damage in Optical Materials: 2011, 81901C (28 November 2011); doi: 10.1117/12.905371
Show Author Affiliations
Zhechao Qu, Institute of Optics and Electronics (China)
Graduate School of the Chinese Academy of Sciences (China)
Yanling Han, Institute of Optics and Electronics (China)
Shengming Xiong, Institute of Optics and Electronics (China)
Bincheng Li, Institute of Optics and Electronics (China)

Published in SPIE Proceedings Vol. 8190:
Laser-Induced Damage in Optical Materials: 2011
Gregory J. Exarhos; Vitaly E. Gruzdev; Joseph A. Menapace; Detlev Ristau; M. J. Soileau, Editor(s)

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