26 August 1996 Stabilized microchip lasers fabricated by micro-optical technologies
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Proceedings Volume 2783, Micro-Optical Technologies for Measurement, Sensors, and Microsystems; (1996) https://doi.org/10.1117/12.248508
Event: Lasers, Optics, and Vision for Productivity in Manufacturing I, 1996, Besancon, France
LETI has developed new reliable and low cost diode pumped solid state microchip lasers using a collective fabrication approach. Very compact microchip lasers consist in small cubes (typically 1 mm3), cut in a wafer of laser crystal with plane parallel polished faces on which dielectric mirrors are deposited. In order to reduce the threshold of plane parallel microchip lasers we have achieved microspherical shapes on laser materials by using a two step micro-optic fabrication technique based on photolithography and melting of photoresist followed by a selectively controlled etching process. These spherical shapes such as microlenses were transferred into the substrate by ion beam milling (IBM), forming microspherical mirrors on the laser cavities. By this way we have also produced large arrays of microlenses of low numerical aperture in silica substrate by using a selectively controlled reactive ion etching (RIE) process. In both etching techniques the selectivity, defined as the ratio between the etching rate of the substrate and the resist, can be adjusted (from 0.1 to 3 in our experiments) by controlling the fraction of oxygen in the gas. Low numerical aperture microlens arrays of 100 to 200 micrometer in diameter and 110 to 250 micrometer in pitch have been made with limits of f/15 in photoresist and f/100 after etching In YAG and f/40 in silica. The laser threshold of stabilized microchip lasers in Nd:YAG with spherical shape of 3 mm in radius of curvature and 150 micrometers in diameter, is then lowered from 40 to 2 mW.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Marc Rabarot, Veronique Tarazona, Engin Molva, Corine Clement, "Stabilized microchip lasers fabricated by micro-optical technologies", Proc. SPIE 2783, Micro-Optical Technologies for Measurement, Sensors, and Microsystems, (26 August 1996); doi: 10.1117/12.248508; https://doi.org/10.1117/12.248508

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