67-mW Continuous-Wave Blue Light Generation by Intracavity Frequency Doubling of a Diode Pumped Cr:LiSrAlF₆ Laser

Abstract

We report a new configuration for an intracavity frequency-doubled Cr-doped LiSrAlF6 (Cr:LiSAF) solid state laser, by inserting a nonlinear crystal of LiB3O5 (LBO) for second harmonic generation (SHG). By applying a highiy reflective coating on LBO crystal, blue light of 67.8 mW was obtained. The slope efficiency of the Cr:LiSAF laser was 39.2% and the continuously tunable wavelength range by a birefringent filter was 113 nm.

Intra-Cavity Nonlinear Frequency Conversion with Cr3+-Colquiriite Solid-State Lasers

“…The most widely studied intracavity nonlinear frequency conversion process in Cr-doped colquiriites has been second-harmonic generation (SHG) in Cr:LiSAF lasers for tunable blue light generation (Balembois et al, 1992;Laperle et al, 1997;Makio et al, 2000). In the following section we will widen the utility of Cr-doped colquiriites to new intracavity frequency conversion processes such as optical parametric oscillation (OPO) and difference frequency generation (DFG).…”

Low‐wavelength emission of Nd‐doped lasers

“…The advantage is that this range can be continuously covered since the emission is broadened to more than 100 nm by vibronic interactions. Tunable blue light has been demonstrated with Ti:sapphire or Cr:LiSAF [18][19][20][21]. However, the problem comes from the pumping wavelength: the absorption bands are shifted in the visible, in comparison to lasers emitting between 900 nm and 1000 nm.…”

Continuous-wave laser at 440 nm based on frequency-doubled diode-pumped Nd:GdVO_4 crystal

“…These lasers are efficient and powerful; nevertheless their wavelengths are too high compared to the 442 nm HeCd laser emission. Other possibilities, e.g., GaN laser diodes emitting a few hundreds of milliwatts [5], or DPSS lasers based on Cr 3+ : LiSrAlF 6 (Cr:LiSAF) crystals intracavity doubled [6], could be considered. However, the first solution is limited by poor spatial beam quality, and the second one is not easily power scalable owing to the bad thermal behavior of the crystal, and to the lack of high brightness of the red laser diode in the absorption band of Cr:LiSAF.…”