UV Bandpass Filter
Optolong’s ultraviolet (UV) optical bandpass filters deliver precise transmission of specific UV spectral bands while blocking out-of-band signals at higher and lower wavelengths. The multi-edge bandpass filters transmit wavelengths defined by a nominal center wavelength (CWL) and bandwidth (FWHM – Full Width Half Max) while reflecting both shorter and longer wavelengths. Also known as thin film or interference filters, Optolong’s bandpass filters use multi-layer hard coatings that provide durable performance without fading or aging in high-output luminaires.
The UV range extends from 200 – 400nm, below human vision and in the responsivity of UV-optimized silicon detectors. Many applications have valuable spectral signatures in the UV region that can be evaluated using precisely positioned bandpass filters.
Dichroic Bandpass Filters vs. Absorption Filters
Unlike absorptive colored glass or polymer gels, these thin film interference filters are virtually absorption-free – providing superior transmission, high-contrast spectral bands, and true lifetime performance. Dichroic bandpass filters can be designed for narrow bandwidths (5 and 10nm typical) or wide bandwidths (50 and 100nm typical). They also have steep edge transitions between the high transmission bandpass and shorter and longer wavelength reflection bands – much steeper than colored glass or polymer gels.
OEM Custom Options
Custom spectral bands are available to match specific bandwidths and cut-on & cut-off wavelengths – engineered for your specific application to deliver the targeted spectral output. These bandpass filters can be patterned on glass optics and wafer-level devices for integrated spectral sensing and imaging. Multiple bandpass filters can also be micro-patterned for multispectral sensing and imaging applications – with potential combinations including UV and visible bands on a common Si sensor. In addition to customized coatings, the optics are delivered in the form to fit your application – in specific substrates, shapes, and sizes.
Integrated Solutions
Bandpass filters are commonly matched or combined with other types of filters to optimize performance in your specific application. In many cases, an optimized OEM design combines multiple coatings onto the same optic to enhance the performance, size, and weight of the device. Some of these complementary filter types include:
- Excitation filters: condition broadband illumination for selective narrowband excitation channels
- Emission filters: bandpass filters around narrowband emission wavelengths to improve contrast and signal-to-noise ratio
- Dichroic beamsplitters: separate emission wavelengths (reflection) from fluorescence wavelengths (transmission)
- Anti-reflective coatings: maximize transmission by reducing reflections due to the index of refraction deltas
- Patterned Bandpass Filters: pixel-scale filter arrays on active devices for application-specific photodiodes and imagers
Applications:
- Forensics & authentication
- UV fluorescence
- Machine vision
- OEM sensing & imaging
- Scientific instrumentation
- Multispectral photodiodes & imagers
Benefits:
- Durable support for high-output lamps, lasers & LEDs
- Lifetime performance – no aging or fading
- High transmission / low absorption
- Spectral stability indoor & outdoor
- Standard & custom colors are available
- OEM customization
Customization Options:
- Bandpass position & width
- Blocking range & level
- Collaborative device engineering
- Substrate, size & shape
- Application-specific photodiodes & imagers
- Wafer level coatings