Patent ID: 7817276
Filing Date: 2010-10-19
Classification: G01N

Abstract:
1. A method of using apparatus that includes an optical cavity component and a photosensing component; the optical cavity component including a light-transmissive region that is partially bounded by first and second light-reflective components such that the light-transmissive region is operable in response to illumination as an optical cavity in which constructive interference occurs in one or more photon energy subranges and destructive interference occurs in other photon energy subranges and that provides output light; each of the first and second light-reflective components having a respective reflection surface toward the light-transmissive region, the respective reflection surfaces being approximately parallel, the light-transmissive region including positions through which, in operation, objects travel in lateral directions approximately parallel to the reflection surfaces; the photosensing component receiving output light from the optical cavity; the method comprising: while objects travel through the light-transmissive region, illuminating the light-transmissive region to operate as an optical cavity in which constructive interference occurs in one or more photon energy subranges and destructive interference occurs in other photon energy subranges, the optical cavity providing output light; the objects traveling through the light-transmissive region in lateral directions approximately parallel to the reflection surfaces; the objects affecting the output light, the output light having a laterally varying intensity function that includes information about the objects while the objects travel through the light-transmissive region; photosensing the output light with the photosensing component to obtain sensing results that depend on the laterally varying intensity function; and using the sensing results to distinguish at least one of the objects.