Pavle Gavrilovic

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.

Stable single-frequency operation of a high-power external cavity tapered diode laser at 780 nm

We report on grating-tuned tapered lasers that oscillate on a single external-cavity mode at powers as high as 720 mW. Frequency stabilization and side-mode discrimination are achieved through the use of an intracavity etalon. The emission frequency was stabilized against mode hops for a period of >2000 s and exhibited a short term jitter of ∼85 MHz over a period of 300 s. The single-frequency emission was tunable over a 17 nm range centered at 783 nm. Furthermore, the far-field emission remained near-diffraction limited throughout the measured current range (<2 A).

1.35 W of stable single-frequency emission from an external-cavity tapered oscillator utilizing fiber Bragg grating feedback

An external-cavity tapered diode laser utilizing fiber Bragg grating feedback was designed to oscillate on a single-longitudinal mode. Stable single-longitudinal mode operation was attained at powers as high as 1.35 W. The emission frequency tuned smoothly with current over the cavity’s free spectral range of 6 GHz. The power in the lasing mode was >30 dB above the background amplified spontaneous emission and the side-mode suppression ratio was >15 dB. No deterioration in the beam quality was measurable up to the highest output power. The coupling efficiency into a Gaussian resonator mode was >65% up to 1.35 W.