High efficiency reflective volume Bragg gratings with chirped gratings
recorded in photo-thermo-refractive glass having an absolute diffraction
efficiency exceeding 95% in transmitting and reflecting modes are used to
stretch and/or compress ultrashort laser pulses with high efficiency.
Robustness, compactness, thermal and laser stability along with placement
of multiple elements in the same space provides femtosecond laser system
with high efficiency of stretching and re-compression of femtosecond
pulses.