LENSES AND OPTICS
Negative Group Delay Dispersion mirrors
10 August 2012
Research Electro-Optics (REO) has introduced a series of negative Group Delay Dispersion (GDD) mirrors for use with industrial ultrafast lasers with an output in the visible or near infrared.
These mirrors can be designed to deliver GDD values as high as -5000fs² (with an accuracy ±10 per cent) at the specific laser wavelength, while also offering excellent reflectivity (>99.8 per cent) as well as high laser damage threshold. Together, these characteristics make these mirrors ideal for intra-cavity use in order to balance out self-phase modulation, and correct for the residual net dispersion due to other components in the laser cavity, including mirrors, windows and crystals. They are also well-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 a high degree of precision and repeatability in terms of layer thickness and refractive index, deposited on to extremely low scatter optical surfaces. REO employs its own enhanced super polishing techniques to achieve micro roughness levels below 0.5Å, resulting in a scattering loss of less than 5ppm. These substrates are coated using ion beam sputtering equipped with REO’s deposition monitoring technology to yield unsurpassed layer precision and low absorption.