Active biosensors with dyed-doped microcavities

In this paper we propose an active biosensor based on dye-doped polymer microcavities. We carried out detailed analysis to show its improved sensitivity. Compared with passive high-Q microcavities, such active sensor can provide 10/sup 5/ fold narrower resonance linewidth in the transmission spectrum at the lasing condition. By detecting the resonance shift due to the presence of analytes in the surrounding solution, such compact active sensors can detect the refractive index change better than 10/sup -9/ in biomedical solutions.