The laser damage threshold of an optical coating, usually referred to as the laser-induced damage threshold or LIDT, is not determined by the coating material alone. It depends on the laser wavelength and temporal regime, beam characteristics, multilayer design, coating defects and absorption, substrate preparation,…
A LiDAR filter’s passband width is set by the receiver’s angle range and temperature range, not by how narrow the coating can be made. Interference filters blue-shift with increasing angle of incidence; a higher effective coating index reduces the shift. Blocking range must match the…
Judge a germanium lens supplier on infrared metrology capability, not on polishing capability alone. Germanium is opaque in the visible, so transmitted wavefront must be measured at infrared wavelengths. Every fringe specification is meaningless without its test wavelength stated on the drawing. Uncoated germanium reflects…
A useful custom optical window specification should define more than material and dimensions. At minimum, it should describe the operating wavelength, substrate or material grade, geometry, thickness, clear aperture, optical quality, surface imperfections, parallelism or wedge, coating performance, angle of incidence, environment, inspection conditions, and…
