Infrared techniques for detecting carbonization at onset of device failure

Norman Farr; Edward L. Sinofsky

doi:10.1117/12.275084

22 May 1997 Infrared techniques for detecting carbonization at onset of device failure

Norman Farr, Edward L. Sinofsky

Proceedings Volume 2970, Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems VII; (1997) https://doi.org/10.1117/12.275084
Event: BiOS '97, Part of Photonics West, 1997, San Jose, CA, United States

Abstract

We describe the design, and development of an infrared detection system which detects the onset of carbonization of fluoropolymers in the presence of up to 60 watts of 1.06 micrometer laser energy. This system is used to shut down a therapeutic laser system before significant damage is done to a laser delivery device and patient. Black body radiation emitting from the diffusion tip is transmitted, backwards, through the same optical fiber as the therapeutic wavelength. Using a high power 1.06 micrometer laser mirror at 45 degrees, most of the 1.06 micrometer light is reflected while the black body radiation is passed to a holographic notch filter which further filters the signal. Still more filtering was needed before the 1.1 to 2 micrometer signal could be detected within the presence the therapeutic light using an extended indium gallium arsenide photodetector. There was still a significant detected offset which increased with laser power which necessitated a means to automatically null the offset for different laser power settings. The system is designed to be used with any unmodified laser system. It interfaces directly to or in series with most common external safety interlocks and can be used with various diffusing tips, probes or bare fibers.

Citation Download Citation

Norman Farr and Edward L. Sinofsky "Infrared techniques for detecting carbonization at onset of device failure", Proc. SPIE 2970, Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems VII, (22 May 1997); https://doi.org/10.1117/12.275084

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