Design and fabrication of tapered polymer microring resonator for single gold nano particle sensing

Detection of nanoparticles with high sensitivity is quite challenging and of paramount importance due to its wide application range in bio-medicine, environmental monitoring and public health monitoring. The optical microresona-tors possess high Q-factor and small mode volume which makes them an ideal platform to detect single nano particles[1]. Gold nanoparticles are inert in nature and easy to synthesis, hence they are used as label for various bio and chemical detections [2]. Thus, detecting small gold particle with high sensitivity holds a strong promise. In this paper, we propose a conventional add-drop racetrack microring resonator with an intermediate tapered section. The tapering of microring resonator increases the strength of evanescent wave which in turn will enhance the sensitivity of the device. We have performed FDTD simulation and carried out theoretical analysis. The proposed device has been fabricated using two-photon polymerization process whose characterization is in the progress.