A Lyot filter (polarization-interference monochromator, birefringent filter),[1]: 106 named for its inventor and French astronomer Bernard Lyot, is a type of optical filter that uses birefringence to produce a narrow passband of transmitted wavelengths.[2][3]: 177 Lyot filters are used in astronomy, particularly for solar astronomy, lasers, biomedical photonics and Raman chemical imaging.[4]: 2.5.2 [5]: 163 [6]: 5.8.3 [7]: 202 [8]: 327 [9]: 14