dichroic mirror

https://doi.org/10.1351/goldbook.DT07356
A mirror used to reflect light selectively according to its wavelength.
Source:
PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 323 (https://doi.org/10.1351/pac200779030293)