In a contrast to other numerous scientific publications on lasers design, this Optics Letters paper reports a remarkably elegant solution based on hybrid microtechnology. The key points of this solution are (1) the development of special semiconductor structures for a high-power, tapered laser diode (LD) with extremely low divergence and Bragg reflectors for wavelength stabilization, optimized for chip technology; (2) precisely calculated and optimized parameters of all-optical components; and (3) high-precision mounting of the LD along with the minioptics and nonlinear crystal on micro-optical bench.
As a result of the application of this elegant hybrid technology, the authors achieved more than 1 W of 532 nm green laser emission with single-pass optical IR to visible conversion of 26%. A special semiconductor structure developed for high-power, narrow line LD emission allowed the generation of second harmonic directly, without an additional stage of solid-state laser pumping by the LD. Because of the high power, narrow line, and perfectly designed waist of the input LD emission in a nonlinear crystal, high frequency conversion efficiency in a single pass was achieved. This design allowed the authors to reject the traditional intracavity second-harmonic generation scheme and make the laser portable, robust, and reliable.
The modern semiconductor technology provides inexpensive LDs emitting at a fixed wavelength in a broad IR range. Because of this possibility, the technology described in this article has an excellent prospective for the production of reliable, robust, cost-effective, efficient, and stable single-frequency lasers in the visible wavelength range for commercial and scientific applications, particularly in Raman microspectrometry and portable flow cytometers.
You must log in to add comments.