Variable attenuator for dual beams

摘要

A variable attenuator for electronically controlling dual beam intensity comprising a laser source for emitting a light beam, a twisted nematic liquid crystal for exposure control of the light beam, a double-sided multi-layer dielectric thin film coated polarization plate for decreasing the s-component of the light beam to less than or equal to 0.0001 of the light beam emitted from the laser source, and a beam splitting crystal for separating said light beam into two beams of equal intensity.