Document Type

Conference Proceeding

Publication Date



Using a simultaneous fitting technique to extract nonlinear absorption coefficients from data at two pulse widths, we measure two-photon and free-carrier absorption coefficients for Ge and GaSb at 2.05 and 2.5 μm for the first time. Results agreed well with published theory. Single-shot damage thresholds were also measured at 2.5 μm and agreed well with modeled thresholds using experimentally determined parameters including nonlinear absorption coefficients and temperature dependent linear absorption. The damage threshold for a single-layer Al2O3 anti-reflective coating on Ge was 55% or 35% lower than the uncoated threshold for ps or ns pulses, respectively. Wavelength-dependant damage threshold modeling is also presented.


Alternative title: Mid-IR Nonlinear Absorption and Damage Study in Ge and GaSb.

Conference location: Santa Fe, New Mexico, 6-10 June 2011

This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States.

Source Publication

Directed Energy Professional Society 24th Annual Solid State and Diode Laser Technology Review