기능

• This is an ND filter used to dim high-power ultraviolet lasers and near-ultraviolet wavelengths.
• Light that does not transmit is not absorbed by the glass, so there is no need to worry about the glass getting hot and breaking.
• Since it is reflected by a metal film, it shows very gentle transmittance wavelength characteristics from ultraviolet to infrared.
• Synthetic quartz is used for the substrate, which has a high transmittance of ultraviolet light, and almost the same transmittance can be obtained in the near-ultraviolet to visible light range.
• The thickness of the glass is 2 mm±0.1 mm and is constant regardless of the transmittance.
• * Since chromium film has absorption, it cannot be used for high-energy pulsed laser.
• * When a high-power laser is injected into the filter, the beam may focus due to the thermal lens effect.
• * Use a variable beam splitter (VBS) for high power lasers and high energy lasers.
• * The laser beam reflected by the surface of the filter is dangerous.
• * Terminate the reflected beam so as not to irradiate the worker.
• * When the laser beam enters the filter normally, the light reflected by the filter returns to the laser light source.
• * When there is such a return light, the laser oscillation becomes unstable.
• * To prevent the return light from returning to the laser source, tilt the filter slightly.
• * The 92% transmittance filter (FNDU-92, MFNDU-92) is a flat board with no coat on both sides.
• * If the reflectivity of the no-coat surface is 4% (8% on both sides), the transmittance becomes about 92%.