title: Bandwidth-variable tunable optical filter unit for illumination and spectral imaging systems using thin-film optical band-pass filters.
abstract: An optical filter unit is demonstrated, which uses two successively arranged tunable thin-film optical band-pass filters and allows for simultaneous adjustment of the central wavelength in the spectral range 522-555 nm and of the spectral bandwidth in the range 3-16 nm with a wavelength switching time of 8 ms∕nm. Different spectral filter combinations can cover the complete visible spectral range. The transmitted intensity was found to decrease only linearly with the spectral bandwidth for bandwidths >6 nm, allowing a high maximum transmission efficiency of >75%. The image of a fiber bundle was spectrally filtered and analyzed in terms of position-dependency of the transmitted bandwidth and central wavelength.
authors: Laser-Forschungslabor, LIFE Center, Klinikum der Universität München, München, Germany. georg.hennig@med.lmu.de
authors: Georg
authors: G
authors: Hennig
authors: Gary M
authors: GM
authors: Brittenham
authors: Ronald
authors: R
authors: Sroka
authors: Gesa
authors: G
authors: Kniebühler
authors: Michael
authors: M
authors: Vogeser
authors: Herbert
authors: H
authors: Stepp
mesh_terms: D008027:Light; D062048:Narrow Band Imaging / Q000295:instrumentation* / Q000379:methods*; D055095:Optics and Photonics / Q000295:instrumentation* / Q000379:methods*; D014172:Transillumination / Q000295:instrumentation / Q000379:methods