Abstract: A laser oscillator has a resonator including a high reflector, an output coupler and a gain medium is positioned in the resonator. A diode pump source is provided, the pump source and gain medium create a lensing effect in the resonator. A shutter is positioned in the resonator and is configured to prohibit oscillation in the resonator until the lensing effect is stabilized. In one embodiment, diode-pumped laser oscillators are provided where damage to intracavity elements, such as SESAM'S, is prevented.

Abstract: The dielectric and/or semiconductor device influences the dispersion of electromagnetic radiation within a given spectral range. It comprises a substrate being essentially transparent to said electromagnetic radiation. The substrate has a first surface for incoupling said electromagnetic radiation into said substrate, and a second surface. The device further comprises a reflective multilayer structure on said second surface, said multilayer structure providing a controlled dispersion characteristic upon reflection of said electromagnetic radiation, e.g., a chirped mirror. The device is arranged in such a way that there is essentially no interference of electromagnetic radiation propagating in the direction of said multilayer structure and electromagnetic radiation reflected by said multilayer structure. An antireflection coating may be provided on the first surface of the substrate. With this device, oscillations in the group delay dispersion can almost completely be avoided.