Microexternal cavity tapered lasers at 670 nm with 5 W peak power and nearly diffraction-limited beam quality

Abstract

Wavelength-stabilized compact laser systems at 670 nm on a micro-optical bench are presented. The resonator concept consists of a tapered semiconductor gain medium and a reflection Bragg grating as a wavelength selective resonator mirror. In pulse operation mode with 100 ns pulses, an optical peak power of 5 W with a spectral width below 150 pm was achieved. Nearly diffraction-limited beam quality at optical output powers up to 1 W is obtained. Such laser systems can be used, e.g., for Raman spectroscopy and as pumping sources for frequency conversion toward UV spectral range.

Wavelength stabilisation during current pulsing of tapered laser

“…Frequency locking and wavelength tuning of a current pulsed external cavity broad area laser diode has been demonstrated with 10 nm tuning range at a peak power of 25 W [4]. Recently, a current pulsed external cavity laser system based on tapered gain media has been demonstrated at 671 nm with up to 5 W peak power at a fixed wavelength [5].…”

Red Tunable High-Power Narrow-Spectrum External-Cavity Diode Laser Based on Tapered Amplifier

“…The tapered laser devices can be used in applications where narrowspectrum is not needed such as photodynamic therapy, but for other applications such as a pump source for UV light generation, the spectral quality of these devices has to be improved. In order to improve the spectral quality of a tapered laser, different techniques are applied, such as a monolithically integrated master oscillator power amplifier by forming Bragg gratings in the semiconductor material (O'Brien et al, 1993(O'Brien et al, , 1997a, injection locking to an external single-mode laser Mehuys et al, 1993b;O'Brien et al, 1997b;Wilson et al, 1998;Ferrari et al, 1999;Spieβberger et al, 2011), and different external-cavity feedback techniques (Jones et al, 1995;Cornwell & Thomas, 1997;Morgott et al, 1998;Goyal et al, 1998;Pedersen & Hansen, 2005;Chi et al, 2005;Lucas-Leclin et al, 2008;Tien et al, 2008;Sakai et al, 2009). Up to 1 W output power at 668 nm from a Fabry-Perot tapered diode laser was obtained with a beam quality factor of 1.7, and the spectral width was smaller than 0.2 nm .…”

“…Around 670 nm, tunable narrow-linewidth diffraction-limited output was also achieved from an injection-locking tapered diode laser system seeded with a single-mode external-cavity diode laser ; the output power was up to 970 mW. A 670 nm micro-external-cavity tapered diode laser system was demonstrated with a reflecting volume Bragg grating as a feedback element; in continuous wave (CW) mode, more than 0.5 W output power was obtained, and in pulse mode, 5 W peak power was obtained with a beam quality factor of 10 and a spectral width below 150 pm (Tien et al, 2008). Up to 1.2 W output power at 675 nm from a tapered laser was obtained with a beam quality factor less than 1.3, the maximum conversion efficiency of 31% was reached at an output power of 1 W .…”

Tunable high-power narrow-spectrum external-cavity diode laser at 675 nm as a pump source for UV generation

“…In order to improve the spectral quality of a tapered laser, different techniques are applied, such as a monolithically integrated master oscillator power amplifier by forming Bragg gratings in the semiconductor material [3,4], injection locking to an external single-mode laser [5,6], and different external-cavity feedback techniques [7][8][9][10][11][12]. Up to 1 W output power at 668 nm from a Fabry-Perot tapered diode laser was obtained with a beam quality factor of 1.7, and the spectral width was smaller than 0:2 nm [13].…”

“…Around 670 nm, tunable narrow-linewidth diffraction-limited output was also achieved from an injection-locking tapered diode laser system seeded with a single-mode external-cavity diode laser [14]; the output power was up to 970 mW. A 670 nm micro-external-cavity tapered diode laser system was demonstrated with a reflecting volume Bragg grating as a feedback element; in continuous wave (CW) mode, more than 0:5 W output power was obtained, and in pulse mode, 5 W peak power was obtained with a beam quality factor of 10 and a spectral width below 150 pm [11]. Externalcavity feedback based on a bulk diffraction grating in the Littrow configuration is a useful technique to achieve a tunable narrow-spectrum, high-power, diffraction-limited tapered diode laser system [7,10]; we have demonstrated such a tapered diode laser system around 668 nm with output power up to 1:38 W; a beam quality factor of 2.0 was obtained with an output power of 1:27 W [15].…”