A novel dual-path high-throughput acousto-optic tunable filter imaging spectropolarimeter

Abstract

It is highly demanding to identify healthy and non-healthy species in a heterogeneous environment such as human tissues. In such a case, one identifier, such as a spectral fingerprint, might be inadequate. Therefore, additional identification is required, for instance, a polarisation measurement. In view of that, the development of a spectropolarimeter that captures two cross-polarised arrays of spectral images is a key requirement. To meet this requirement, an imager optical setup has been designed to provide spatial, spectral and polarisation preference information for species that exist in a heterogeneous environment, such as in medical tissue samples. The spectral and polarisation information is obtained employing an acousto-optic tunable filter and a polarising beam splitter, respectively. The optical imager is designed to operate in the visible-near infrared range (450–850 nm) with a spectral resolution of 3 nm. The spectropolarimeter design along with optical characterisation results are reported.