KEYWORDS: Absorption, Transmittance, Germanium, Laser damage threshold, Free electron lasers, Infrared radiation, FT-IR spectroscopy, High power lasers, Mid-IR, Laser energy
We have observed and characterized wavelength-dependent laser damage thresholds in crystalline germanium induced
by trains of high-power infrared picosecond laser pulses at wavelengths ranging from 2.8 μm to 5.2 μm, using the
Vanderbilt Free-Electron Laser. In this wavelength range, photon energies are well below the band-gap energy. As the
wavelength is increased, threshold fluences are observed to increase by a factor of five over the studied wavelength
range. Two- and three- photon absorption is the predominant photon energy absorption mechanism up to 4.4 μm. At
wavelengths above 4.8 μm tunnel absorption appears to be the primary absorption mechanism. Wavelength and fluence
dependent transmission and reflection measurements provide valuable insight into the nature of the damage mechanisms.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.