Short-pass filters

Short-pass filters transmit short wavelengths and block long wavelengths

Short-pass filters are a type of edge filter characterized by a narrow transition between the blocking and transmission ranges. The wavelength that separates the absorption and transmission regions is known as the "cut-off" wavelength. Optical edge filters, therefore, feature two distinct spectral ranges: a transmission range and a blocking range, which are sharply separated. Short-pass filters transmit all wavelengths shorter than the cut-off wavelength and block wavelengths longer than the cut-off. After the cut-off, short-pass filters reflect and block longer wavelengths, effectively separating short-wavelength radiation from long-wavelength radiation and reducing unwanted extraneous radiation. The transition between the short-wavelength transmission range and the long-wavelength blocking range can be made very sharp.

Short-pass filters are typically designed for an incident angle of 0°. However, we also offer dichroic short-pass filters optimized for higher angles of incidence, such as 45°. Additionally, short-pass edge filters can serve as hot mirrors, reducing unwanted heat caused by infrared radiation, and acting as heat-protection filters.

• High transmission allows short wavelengths to pass
• Long wavelengths are blocked by high reflection
• Optimum light throughput
• Position of the edge is adjustable, specific wavelengths can be well isolated by steep edges
• Stable cut-off wavelengths
• Minimization of reflections in optical systems
• Reduction of unwanted stray light due to strong blocking and high optical density
• Interference filters can be designed with a steeper edge than color glass filters
• Spectral range: UV to IR
• Substrates: Borofloat, B270, float glass, selected plastics, etc.