Diffraction-limited 577 nm true-yellow laser by frequency doubling of a tapered diode laser

Abstract

A wide range of laser medical treatments are based on coagulation of blood by absorption of the laser radiation. It has, therefore, always been a goal of these treatments to maximize the ratio of absorption in the blood to that in the surrounding tissue. For this purpose lasers at 577 nm are ideal since this wavelength is at the peak of the absorption in oxygenated hemoglobin. Furthermore, 577 nm has a lower absorption in melanin when compared to green wavelengths (515 -532 nm), giving it an advantage when treating at greater penetration depth. Here we present a laser system based on frequency doubling of an 1154 nm Distributed Bragg Reflector (DBR) tapered diode laser, emitting 1.1 W of single frequency and diffraction limited yellow light at 577 nm, corresponding to a conversion efficiency of 30.5%. The frequency doubling is performed in a single pass configuration using a cascade of two bulk non-linear crystals. The system is power stabilized over 10 hours with a standard deviation of 0.13% and the relative intensity noise is measured to be 0.064 % rms.

2.7 W diffraction-limited yellow lasers by efficient frequency doubling of high-brightness tapered diode lasers

“…It is clear that within the diode-based technologies, our laser system shows an enhanced performance in terms of both power and conversion efficiency. Preliminary CW results of a 1-W yellow laser were reported by our group in [22]. In this work, we significantly increase the yellow output power up to 2.7 W while maintaining the near-diffraction-limited beam quality.…”