High Power Mirrors

A high-power mirror must be able to withstand very high radiation powers and must not suffer any damage even during prolonged irradiation. The damage threshold LIDT is the benchmark for the resistance of the optics.

LIDT is dependent on numerous parameters. Both layer properties (e.g. thermal properties, cleanliness, band gap) and substrate properties (e.g. material, surface quality) must be matched to the application parameters (e.g. wavelength, pulse duration, repetition rates, beam diameter, vacuum vs. atmosphere composition).

In the laser process, optics are affected by three dominant destruction mechanisms:

  • • cw – ns → thermal destruction due to absorption within the coating material.
  • • ns – ~20ps → local heating due to absorption at defects.
  • • ~20ps – fs and shorter → destruction by ionization effects.
  Dominant destruction mechanisms at different pulse lengths

We produce optics with very high destruction thresholds. Confirmed destruction thresholds of selected LAYERTEC optics are summarized in the Technical Report.

Mirror after measuring the LIDT: The visible dots are laser-induced damages in the coating