Shobha Singh

HIGH-POWER 390-NM LASER SOURCE BASED ON EFFICIENT FREQUENCY DOUBLING OF A TAPERED DIODE LASER IN AN EXTERNAL RESONANT CAVITY

We frequency doubled the single-frequency beam from an external-cavity tapered laser diode operating at 780 nm in a resonant cavity containing a beta -barium borate crystal to generate an output at 390 nm with high efficiency. Output powers as great as 233 mW were obtained, corresponding to an efficiency of 65%/W . The resonant-cavity design was a low-loss three-mirror configuration that provided compensation for astigmatism and coma. The laser diode frequency was locked to the doubling-cavity resonance by use of the Hänsch-Couillaud discrimination technique.

Persistent spectral hole burning at liquid nitrogen temperature in Eu 3+‐doped aluminosilicate glass

The observation of persistent spectral hole burning (PSHB) in Eu3+‐doped aluminosilicate glass at 77 K is reported in this letter. The homogeneous linewidth of the 7F0→ 5D0 transition is measured to be ∼0.5 A by both PSHB and fluorescence line narrowing techniques. The ratio of inhomogeneous‐to‐hole widths at 77 K is 45. The 7F0→ 5D0 transition is visible directly in transmission due to the high concentration of Eu3+.

High‐power, single‐frequency diode‐pumped Nd:YAG microcavity lasers at 1.3 μm

A single‐frequency output power of 210 mW on the 1.3 μm transition was obtained from a monolithic YAG laser doped with 4.2% Nd. Lasers fabricated from high Nd‐concentration YAG crystals oscillated simultaneously on the 1.319 and 1.338 μm lines at high pump power, but in a single axial mode at both wavelengths. The oscillation frequency was continuously temperature‐tunable at a rate of 3.6 GHz/ °C over a range of 170 GHz (10 A). The emission was linearly polarized with an extinction ratio ≳1000:1. In two‐wavelength operation, the 1.319 and 1.338 μm transitions were orthogonally polarized.

Temperature-tunable, single frequency microcavity lasers fabricated from flux-grown YCeAG:Nd

Data are presented on a single‐frequency, diode‐pumped, microcavity YCeAG:Nd laser. The maximum output power was 45 mW in continuous operation, limited by the available pump power of 250 mW. The output was single‐frequency, TEM00 at all powers. The lasing frequency was continuously temperature‐tunable over a range greater than 180 GHz, with a stability of better than 10 MHz.

INTRACAVITY, FREQUENCY-DOUBLED, MINIATURIZED ND:YALO3 BLUE LASER AT 465 NM

A blue laser at 465 nm has been demonstrated by intracavity frequency doubling of the 930 nm transition in neodymium‐doped crystal of yttrium orthoaluminate (Nd:YAlO3). The compact plano–plano laser cavity comprising a 1.2‐mm‐thick Nd:YAlO3 crystal and a 1.3 mm potassium niobate (KNbO3) crystal generated more than 15 mW of blue power when pumped by a Ti:sapphire laser. The blue output is linearly polarized with a TEM00 spatial profile.