An accurate digital instrument for the measurement of circular polarisation of luminescence

Abstract

An apparatus to detect circular polarisation of luminescence (CPL) is described. The instrument, involving a digital synchronous sampling photon counting system and an effective square-wave modulation, is absolute and has a high sensitivity. Its baseline is flat and stable, enable prolonged measurements to detect small degrees of circular polarisation, to study poorly fluorescing compounds or to detect circular polarisation in chemiluminescence. An additional advantage is that the instrument can be simply switched to measure linear polarisation.