Verbesserung der Emissionseigenschaften substratseitig emittierender Vertikallaserdioden
FacultiesFakultät für Ingenieurwissenschaften und Informatik
Improved emission properties of bottom-emitting vertical-cavity lasers - Vertical-cavity surface-emitting lasers (VCSELs) and related devices operating in the 980 nm spectral region are of interest for many applications like pumping of solid-state lasers or optical amplifiers as well as frequency doubling for visible laser light generation. Such applications require high-power laser sources with high beam quality. Optical output powers in the watt range and even hundreds of watts have been generated with single bottom-emitting VCSELs and two-dimensional arrays, respectively. However, these sources exhibit multimode operation and a low beam quality. The use of an extended cavity defined by one distributed Bragg reflector (DBR) of the VCSEL chip and an external curved mirror (Vertical extended-cavity surface-emitting lasers, VECSELs) allows to achieve lasing in a single transverse optical mode with high beam quality. In this thesis, bottom-emitting vertical-cavity lasers have been investigated with regard to high output power, transverse mode control and improved beam quality. The work includes fabrication, mounting and characterization of VCSELs as well as of electrically pumped VECSELs. Furthermore, intracavity frequency doubling of VECSELS establishing a blue light source emitting near 485 nm wavelength is presented. In another study, the monolithic integration of curved dielectric mirrors with VCSELs has been investigated, yielding compact single-mode high-power lasers. The lasers operate at room temperature in a stable single mode with continuous-wave output powers up to 15 mW. The presented device design demonstrates the feasibility to realize single-mode VCSELs with maximum output powers exceeding those reported in the literature so far.
Subject HeadingsFrequenzverdopplung [GND]