cut-off filter

https://doi.org/10.1351/goldbook.C01482
An optical device which only permits the @T06477@ of radiation of wavelengths that are longer than or shorter than a specified @W06659@. Usually, the term refers to devices which transmit radiation of wavelengths longer than the specified @W06659@.
See:
filter (of a radiation)
Source:
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2234 [Terms] [Paper]