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Holographic Laser Bandpass Filters
Our Holographic Laser Bandpass Filters are fabricated by recording interference patterns formed between two mutually coherent laser beams, unlike conventional interference filters, which are made by vacuum evaporation techniques. These filters represent a major technical breakthrough in the optical filtering of unwanted plasma lines or fluorescence from laser sources. By using the unexpanded laser beam and combining high laser throughput with narrow spectral bandwidth, the Holographic Bandpass Filter provides the user with a previously unattainable level of performance.
*Spectral bandwidth is dependent on the size and positioning of a user-supplied aperture on the output beam. Generally, smaller apertures further from the filter will result in narrower bandwidths. Theory of Operation
The Holographic Bandpass Filter consists of a volume transmission grating located between two prisms. A collimated S-polarized laser beam is directed perpendicularly into the cube. The internal transmission grating diffracts the laser line through 90 degrees so that the output beam is nominally perpendicular to the exit face of the cube. The grating is spectrally selective so only the light which is very close to the design wavelength of the filter is diffracted. The undiffracted light passes through the back face of the cube. Unwanted light with wavelengths near the laser line is diffracted by the transmission grating but at a different angle than the laser line. This unwanted diffracted light can be removed by a spatial filter (slit or aperture) located beyond the exit face of the cube. Request product information online | Filter sales contact info |
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