Titanium:Sapphire Pump Mirrors
Research Electro-Optics, Inc. (REO)
BOULDER, Colo., Jan. 22, 2013 — REO has introduced an expanded series of ultrafast dichroic pump mirrors designed to support femtosecond Ti:sapphire lasers. This is achieved through the use of thin-film coatings that generate negative group delay dispersion (GDD) to compensate for the positive GDD caused by other cavity components.
The focusing concave optics provide broadband performance, delivering >99.7% reflectivity over the 675- to 1100-nm wavelength range, while providing >98% transmission at the 532-nm pump wavelength. The broadband reflectivity makes the optics suitable for use in virtually any Ti:sapphire oscillator, particularly one-box models. Examples include broadband (very short pulse) oscillators, widely tunable oscillators for microscopy and spectroscopy, and fixed-wavelength oscillators for seeding ultrafast amplifiers.
Even if it produces broadband output, a femtosecond laser oscillator’s pulse width is often limited by positive GDD, caused principally by the transmissive optics in the laser cavity, including the Ti:sapphire crystal. This can be partially offset by the use of reflective cavity optics with negative GDD. The enhanced pump mirrors from REO typically deliver up to 100 fs2
of negative GDD and are designed for minimum third-order dispersion to simplify the laser designer’s task of achieving the shortest possible transform-limited pulse width.
The spherical mirrors are offered with a radius of curvature of 10, 15 or 50 cm, with flats and other radius values available upon request. Standard diameters are 7.75, 12.75 and 19 mm.