A Polarization-Independent Pulsed-Laser Energy Monitoring System with Analog Readout
Laser beam monitors commonly use a single optical plate placed at an angle to the beam to divert a fraction of the laser beam to a detector. If the beam is not polarized or is polarized in one direction only, the use of a single plate causes no sampling error for an energy measurement. However, if different lasing modes have different polarizations, each mode may be reflected to a different extent due to the nonzero angle of incidence. For instance, Fresnel’s laws of reflection’ predict that a glass plate with a refractive index of 1.55 at a 45° angle of incidence reflects 10.4% of parallel polarized light and 1.1% of perpendicularly polarized light at each surface, assuming that the reflections at the two surfaces of the plate do not interfere with each other.
KeywordsBias Current Powder Layer Strip Chart Recorder Sample Beam Voltage Comparator
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