TUNABLE OPTICAL FILTER

摘要

An apparatus for performing spectroscopy incorporates, between an EM source and a detector, an optical filter comprising a pair of mirrors opposed along the optical axis and shaped to provide an optical cavity with stable resonance and having a cavity length of at most 50 μm and a mode at a wavelength within said band of wavelengths for bandpass filtering EM radiation passing therethrough. The actuator system is arranged to move the mirrors relative to each other along the length of the optical cavity for tuning the wavelength of said mode.

主权项

1. A method of filtering EM radiation in an apparatus for performing spectroscopy that comprises, arranged along an optical axis:
an EM source arranged to generate EM radiation having a band of wavelengths for illuminating a sample; a sample holder arranged to hold the sample; and a detector for detecting EM radiation transmitted through the sample, the method comprising: providing, within the apparatus between the EM source and the detector, an optical filter comprising a pair of mirrors opposed along the optical axis and shaped to provide an optical cavity with stable resonance and having a cavity length of at most 50 μm and a mode at a wavelength within said band of wavelengths for bandpass filtering EM radiation passing therethrough, and further providing an actuator system arranged to move the mirrors relative to each other along the length of the optical cavity for tuning the wavelength of said mode.