N. Ruhnke, A. Müller, B. Eppich, M. Maiwald, B. Sumpf, G. Erbert, G. Tränkle

Published in:

Proc. SPIE 9382, Photonics West, San Francisco, USA, Feb. 07-12, 93820P (2015).

Abstract:

Recently, high-power broad-area laser diodes based on GaN with output powers beyond 1 W have become available. However, their broad spectral emission limits their applicability. Due to a lack of internal grating technology for GaN devices, narrowband emission with several hundreds of milliwatts in the blue-green spectral range has not been achieved with laser diodes thus far. In this work, a high-power external cavity diode laser (ECDL) system at 445 nm is presented. The system is based on a commercially available broad-area GaN laser diode and a surface diffraction grating in Littrow configuration for optical feedback. Using this configuration an output power of 400 mW with a reduced spectral emission bandwidth of 20 pm (FWHM) with a side-mode suppression ratio larger than 40 dB is obtained. With the above presented optical output power and narrowband laser emission at 445 nm, the ECDL is well suited as a pump light source for nonlinear frequency conversion into the deep ultraviolet spectral range.

Keywords:

Laser diode, GaN, External cavity diode laser, Littrow configuration, Narrow linewidth.

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