A beam sampler inserted in the main path to divert a percent or so of the power to a photodiode, power meter, spectrometer or camera while the rest goes on. Uncoated fused silica wedges reflect about 3.5 percent per surface near normal incidence, and the wedge angle separates the front and back reflections and avoids etalon fringes. Polarization-dependent reflection means the sampled fraction changes with input polarization.
Put a pickoff after the compressor and feed the photodiode, I want to log pulse energy for the whole run.
Also heard as
- pick-off
- beam sampler
- sampling wedge
Related terms
Beam profiler
An instrument, usually a camera or scanning slit, that measures a laser beam's intensity distribution and width.
Ghost
A weak stray beam from a back-surface reflection that travels off in an unexpected direction or focuses somewhere it should not.
AR coating
Antireflection coating: thin dielectric layers that cut surface reflections from about 4 percent to a fraction of a percent.
Beam dump
A device that absorbs an unwanted or terminated laser beam completely and safely, without reflecting it.