Negative GDD Mirrors
Aug 2012Research Electro-Optics Inc. (REO)Request Info
BOULDER, Colo., Aug. 14, 2012 — REO has introduced negative group delay dispersion (GDD) mirrors for use with industrial ultrafast lasers having output in the visible or near-infrared.
The mirrors deliver GDD values as high as −5000 fs2 with accuracy of ±10% at the specific laser wavelength, while offering >99.8% reflectivity and a high laser damage threshold. They are suitable for intracavity use to balance out self-phase modulation and to correct for the residual net dispersion caused by other components in the laser cavity, including mirrors, windows and crystals. They are also suited for use in extra-cavity applications, such as for turning mirrors, and in pulse compression systems.
Producing GDD correction optics requires thin-film coating with precision and repeatability in terms of layer thickness and refractive index, deposited onto low-scatter optical surfaces. Proprietary enhanced superpolishing techniques achieve microroughness levels below 0.5 Å, resulting in a scattering loss of <5 ppm. The substrates are coated using ion beam sputtering equipped with a proprietary deposition monitoring technology to yield layer precision and low absorption.
The mirrors are supplied on fused silica substrates, in diameters of up to 3 in., with flatness of λ/20 at 633 nm, surface quality of 10-5 over an 80% clear aperture, and zero defects achievable over controlled subapertures. Nominal incidence angles in the 0° to 45° range can be accommodated.
Custom mirrors also are available.