Patent ID: 6356675
Filing Date: 2002-03-12
Classification: G01N,G02B

Abstract:
A device for detecting a change &Dgr;n in the index of refraction nl of a liquid between the values nl and nl âˆ’&Dgr;n, comprising:a short length of optical guide having refractive index ng, said guide having a smooth exterior surface along its length covered by the liquid; means for inputting a light beam into said guide, the angle of the light beam with respect to said optical guide being selected so that light impinges on the interface between said exterior surface and the liquid at the lowest critical angle &phgr;c of said guide, where &phgr;c =sinâˆ’1(nl âˆ’&Dgr;n)/ng; and means for detecting the change in light passing through said guide.