Laser-induced damage threshold, LIDT, is stated in J/cm squared for pulsed lasers at a specific wavelength and pulse duration, and in W/cm or W/cm squared for CW beams. Nanosecond values scale roughly with the square root of pulse duration, a rule that breaks down for picosecond and femtosecond pulses. Real-world damage starts at defects, dust and hot spots, so designs keep peak fluence at half or less of the rated value.
Mirror's rated 10 J/cm squared at 10 ns and 1064, we're running 8 ns at 7, that's too close with this beam profile.
A damage spec for one wavelength and pulse duration says almost nothing about another, so ask the vendor for test data at your conditions.
Also heard as
- LIDT
- laser damage threshold
- damage spec
Related terms
Fluence
Pulse energy per unit area, usually in J/cm squared, the quantity that sets ablation and optical damage.
Hot spot
A small region of a beam with much higher intensity than the rest, a common cause of optic damage.
AR coating
Antireflection coating: thin dielectric layers that cut surface reflections from about 4 percent to a fraction of a percent.
Peak power
The highest instantaneous power reached during a laser pulse, roughly pulse energy divided by pulse duration.
Fried
Lab slang for a laser diode, optic, coating or detector that has been destroyed by too much light or current.