PROBLEM TO BE SOLVED: To enable more efficient separation of light with less optical filter elements.;SOLUTION: An optical filter element according to an embodiment of the present invention comprises a pair of reflection surfaces disposed in parallel at a predetermined interval to constitute a Fabry-Perot resonator. At least one of the pair of the reflection surfaces is a wavelength selective reflection surface containing a dielectric multilayer film, which has a vacuum layer or a gas layer disposed between a pair of reflection films such that narrowband light having a center wavelength within an absorption band of a prescribed biological substance is allowed to selectively transmit and the center wavelength varies according to the incident angle.;COPYRIGHT: (C)2015,JPO&INPIT
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