High-Efficiency Tunable Fluorescence Emission Filter

Tunable filters developed by us, based on electrically-tuned liquid crystal waveplates, providefluorescence microscopists with fast, continuous and automated selection of emission wavelengthwithout vibration, image shift, or detectable degradation of image quality. They can be used to convertany high-resolution monochromatic camera into a multispectral camera. On the other hand, these liquidcrystal tunable filters (LCTF's) presently offer rather low throughput (10 to 25%) which limits theirusefulness in photon-limited fluorescence applications. Our aim is to determine the feasibility ofdeveloping a new type of liquid crystal tunable filter with efficiency of 70% or more. Improvements inefficiency will accrue mainly from: 1) use of a novel optical configuration that filters all input polarizationstates instead of just one linear polarization state; and 2) improving the efficiency of our liquid crystaltunable waveplates.