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Proceedings Paper

Intracavity frequency-doubled degenerate laser (Conference Presentation)
Author(s): Hui Cao; Seng Fatt Liew; Sebastian Knitter; Sascha Weiler; Jesus F. Monjardin-Lopez; Mark Ramme; Brandon Redding; Michael A. Choma M.D.

Paper Abstract

Visible lasers have a wide range of applications in imaging, spectroscopy and displays. Unfortunately, they suffer from coherent artifacts such as speckle. Various compounding techniques have been developed to remove speckle, but these methods usually involve mechanically moving parts and require long acquisition times. A different approach to prevent speckle formation is developing lasers with low spatial coherence. A careful design of the laser cavity can facilitate lasing in many spatial modes with distinct emission pattern. The total emission from those mutually incoherent lasing modes has low spatial coherence. To date, several types of such lasers have been developed, but most of them have emission beyond the visible spectrum, making them unsuitable for imaging or display applications that require visible light.

An alternative way of making visible sources, especially of green color, is frequency doubling of infrared (IR) lasers. We develop a green light source with low spatial coherence via intracavity frequency doubling of a solid-state degenerate laser. The second harmonic emission is distributed over a few thousands independent transverse modes, and exhibits low spatial coherence. A strong suppression of speckle formation is demonstrated for both fundamental and second harmonic beams. Using the green emission for fluorescence excitation, we show the coherent artifacts are removed from the full-field fluorescence images. The achievable high power, low spatial coherence, and good directionality make the green degenerate laser an attractive illumination source for parallel imaging and projection display.

Paper Details

Date Published: 21 April 2017
PDF: 1 pages
Proc. SPIE 10088, Nonlinear Frequency Generation and Conversion: Materials and Devices XVI, 1008807 (21 April 2017); doi: 10.1117/12.2251503
Show Author Affiliations
Hui Cao, Yale Univ. (United States)
Seng Fatt Liew, Yale Univ. (United States)
Sebastian Knitter, Yale Univ. (United States)
Sascha Weiler, TRUMPF Inc. (United States)
Jesus F. Monjardin-Lopez, TRUMPF Inc. (United States)
Mark Ramme, TRUMPF Inc. (United States)
Brandon Redding, Yale Univ. (United States)
Michael A. Choma M.D., Yale Univ. (United States)

Published in SPIE Proceedings Vol. 10088:
Nonlinear Frequency Generation and Conversion: Materials and Devices XVI
Konstantin L. Vodopyanov; Kenneth L. Schepler, Editor(s)

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