Importance

Loading Importance Indicators...

Abstract

An apparatus for detecting a UV signal in the presence of background solar radiation comprises: a first filter system disposed along an optical axis being responsive to a light flux containing background solar radiation and a UV signal for passing UV light wavelengths below a selected UV wavelength and having a very sharp wavelength cutoff to substantially block wavelengths within a first selected wavelength band above the first selected UV wavelength; second and third filter systems serially disposed along the optical axis and tilted off the optical axis with respect to each other are selectively responsive to light from the first filter system for sequentially passing UV light wavelengths below the selected UV wavelength and substantially blocking visible light within the first selected wavelength band; a downconverter transforms the UV signal light from the third filter system to visible light in a second selected wavelength band; a dielectric coating disposed adjacent to the downconverter and between the third filter system and the downconverter for passing the UV signal light into the downconverter and for reflecting the visible light produced by the downconverter; a fourth filter system responsive to light from the downconverter for blocking all wavelengths greater than 700 nm that may have passed through the first, second and third filter systems and for passing therethrough the visible light in the second selected wavelength band; and a photomultiplier tube for detecting the visible light in the second selected wavelength band.

Loading the Abstract Image...

First Claim