US 6,393,038 B1 · Frequency-doubled vertical-external-cavity surface-emitting laser

Abstract

A frequency-doubled semiconductor vertical-external-cavity surface-emitting laser (VECSEL) is disclosed for generating light at a wavelength in the range of 300-550 nanometers. The VECSEL includes a semiconductor multi-quantum-well active region that is electrically or optically pumped to generate lasing at a fundamental wavelength in the range of 600-1100 nanometers. An intracavity nonlinear frequency-doubling crystal then converts the fundamental lasing into a second-harmonic output beam. With optical pumping with 330 milliWatts from a semiconductor diode pump laser, about 5 milliWatts or more of blue light can be generated at 490 nm. The device has applications for high-density optical data storage and retrieval, laser printing, optical image projection, chemical-sensing, materials processing and optical metrology.

Claims38

Dependent claims

An apparatus for generating light at a second-harmonic frequency, comprising:

(a) a semiconductor substrate including a first reflector formed thereon and a semiconductor active region formed on the substrate above the first reflector;
and
(b) a nonlinear crystal located proximate to the active region and spaced therefrom by an air gap, with the nonlinear crystal including a second reflector on a surface thereof away from the active region, the first and second reflectors defining therebetween a laser cavity containing the active region and the nonlinear crystal, with the active region generating lasing light at a fundamental frequency in response to electrical or optical activation, and with the nonlinear crystal converting a portion of the lasing light into light at the second-harmonic frequency.

A semiconductor laser, comprising:

(a) a gallium arsenide substrate having a plurality of III-V compound semiconductor layers epitaxially grown thereon, including a plurality of alternating high-refractive-index and low-refractive-index semiconductor layers forming a first reflector which is reflective of light at a fundamental frequency, and an active region wherein light is generated at the fundamental frequency;
and
(b) a nonlinear crystal separated from the substrate and plurality of semiconductor layers by an air gap, the nonlinear crystal having a first surface and a second surface, with the first surface nearest the substrate including an anti-reflection coating thereon, and with the second surface being curved and including a second reflector which is reflective of the light at the fundamental frequency and transmissive of light at a second-harmonic frequency that is twice the fundamental frequency, the first and second reflectors defining therebetween a laser cavity that extends from the first reflector through the active region and the nonlinear crystal to the second reflector, with the laser being responsive to an external energy source to generate light in the laser cavity at the fundamental frequency, and with the nonlinear crystal being operative to convert the light at the fundamental frequency to light at the second-harmonic frequency, thereby generating an output light beam at the second-harmonic frequency through the second reflector.

Dependencies are inferred from the claim text.

Frequency-doubled vertical-external-cavity surface-emitting laser

Life of this patent

Frequency-doubled vertical-external-cavity surface-emitting laser

Life of this patent

Abstract

Claims38