The crystal, oven and mount assembly that does second harmonic generation, or a complete add-on module for that job. A doubled YAG makes 532 nm green from 1064 nm, and doubled Ti:sapphire makes blue around 400 nm. Tripler and quadrupler follow the same naming for third and fourth harmonics, and people say the doubler is detuned when conversion drops.
Green output's fine, the doubler's peaked, the IR leak behind the separator is the thing that worries me.
Also heard as
- SHG crystal
- doubling crystal
Related terms
SHG
Second Harmonic Generation: converting light to exactly double its frequency, half its wavelength, in a nonlinear crystal.
Oven
The temperature-controlled mount that holds a nonlinear crystal at its phase-matching temperature.
YAG
Shorthand for yttrium aluminum garnet, and in practice for the Nd:YAG laser at 1064 nm.
Bleed-through
Residual unwanted wavelength, such as leftover infrared pump, leaking past filters into the useful beam.