An optical bandpass filter is an element that allows wavelengths within a certain range to pass through and blocks any wavelengths outside of that range. These filters are often used for fluorescence microscopy, imaging, and spectroscopy among other applications.
The passband is the range of the spectrum that is allowed to pass through the bandpass filter. Ideally, these filters would have a passband that does not have any attenuation throughout, and would completely block all wavelengths outside of the passband.
It is difficult to achieve the perfect optical bandpass filter, as there is often a region outside of the passband where the wavelength is attenuated to very low levels (1/1,000,000) but not completely rejected. Optical bandpass filters from Delta Optical Thin Film are made to the highest specifications and aim to reduce transmission outside the passband to a level suited for the specific application. Our standard bandpass filters are available as narrow band and broad band filters. All of these filters are ultra-hard coated and the standard dimension is Ø25 mm (with ring). If required, we can manufacture other custom dimensions.
Bifrost Continuously Variable Bandpass Filters
In addition to the standard range of optical bandpass filters, Delta Optical Thin Film manufacture custom Bifrost Continuously Variable Bandpass Filters for mid-size and full-frame CCD/CMOS sensors.
These bandpass filters are ideal for silicon-based detectors due to the extremely high transmission, and they are fully blocked in the light-sensitive wavelength range of these detectors. The use of these filters with silicon detectors enables compact, robust, and affordable Hyperspectral Imaging detectors to be designed. These detectors provide many advantages over traditional approaches as they have a huge aperture, higher transmission, and shorter measurement time. Additionally, they provide a high suppression of stray light, and they have excellent signal to noise ratio.
We are able to design completely custom Bifrost Continuously Variable Bandpass Filters depending on the application requirements. We also have filters available for immediate testing with various center wavelength ranges.
Delta Optical Thin Film has over 50 years of experience of manufacturing optical thin film components, including bandpass filters. Our advanced optical coatings allow us to provide the world leading manufacturers of analytical measurement instruments with the best optical capabilities.