Polarization switching in a mid-infrared Er:YAlO3 laser.

We report on a polarization-resolved study of mid-infrared emission properties of Er3+-doped orthorhombic yttrium aluminum perovskite YAlO3 single crystal. For the 4I11/2 → 4I13/2 Er3+ transition, the stimulated emission cross section is 0.20 × 10-20 cm2 at 2919 nm for light polarization E ‖ c. Pumped by an Yb-fiber laser at 976 nm, the 10 at.% Er:YAlO3 laser delivered 1.36 W at 2919 nm with a slope efficiency of 31.4%, very close to the Stokes limit, a laser threshold as low as 33 mW and a linear polarization. Pump-induced polarization switching between E || b and E || c eigen states was observed and explained by excited-state absorption from the terminal laser level.

Laser performance of high optical quality 4 at.% Pr3+: Sr0.7La0.3Mg0.3Al11.7O19 (Pr:ASL) single crystals.

In this work, we present the visible laser performance of improved optical quality Czochralski-grown 4 at.% Pr3+-doped Sr0.7La0.3Mg0.3Al11.7O19 (Pr:ASL) single crystals in the deep red (726 nm), the red (645 nm) and the orange (620 nm) range using two different pumping sources. Using a high beam quality frequency doubled Ti:sapphire laser with 1 W output power as pump source, deep red laser emission was reached at a wavelength of 726 nm with 40 mW of output power and a laser threshold of 86 mW. The corresponding slope efficiency was 9%. At 645 nm in the red, up to 41 mW of laser output power were obtained with 15% slope efficiency. Moreover, orange laser emission at 620 nm was demonstrated with 5 mW output power and 4.4% slope efficiency. Using a 10 W multi-diode module as pumping source allowed to obtain the highest output power of a red and deep-red diode-pumped Pr:ASL laser to date. The respective output powers at 726 and 645 nm reached 206 mW and 90 mW.

High peak-power near-MW laser pulses by third harmonic generation at 355†nm in Ca5(BO3)3F nonlinear single crystals.

In this work, the performance of Ca5(BO3)3F (CBF) single crystals was investigated for the third harmonic generation at 355 nm. A high energy conversion efficiency of 16.9% at 355 nm was reached using a two-conversion-stage setup. First, using a high peak power, passively Q-switched Nd3+:YAG/Cr4+:YAG microlaser based gain aperture in micro-MOPA, the second harmonic at 532 nm was achieved with lithium triborate (LBO) crystal, reaching 1.35 MW peak power. On a second step, laser pulses at 355 nm were generated using a 5 mm-long CBF crystal growth by TSSG method with energy, pulse duration and peak power of 479 µJ, 568 ps and 0.843 MW, respectively. These results are currently the highest reported for CBF material.