Notch filters are band blocking filters. They are used to suppress strong laser beams in Raman laser spectroscopy and other applications. They may also be employed to protect eyesight or used as attachable filters for cameras.
Notch Filters Transmission. Image Credit: Laser Components (UK) Ltd.
At the centre wavelength (CWL), the blocking is > OD 4 or > OD 6. At all other wavelengths outside this blocking range, the filters provide >90% transmission. Depending on the wavelength, the full width at half maximum range (FWHM) typically covers 10 to 70 nm.
In addition to the standard notch wavelengths, we also offer filters for other, "unusual" wavelengths as well as multi-notch designs for multiple stop bands. All these customised solutions feature >OD 8 by design, transmission up to 98% and a high cavity (steep-edged).
Special - Dichroic Notch Filters
Dichroic notch filters are band stop designs that reflect the notch wavelength with up to >98% at an angle of incidence of 45°. Shorter and longer wavelengths beyond the notch wavelength are transmitted with up to >95%.
Source: https://www.lasercomponents.com/uk/