Ultracompact high-sensitivity biochemical sensor built with photonic crystal nanobeam cavity

For the utilization as sensors, photonic crystal (PhC) cavities with strong light matter interaction between the optical fields and the analytes are preferred. However, there is a trade-off between sensitivity (S) and quality factor (Q): the optical mode should be distributed more into the target analytes to achieve a higher S; while in order to obtain a high Q, the confinement of the optical mode in the wave-guiding medium have to be large. We demonstrated ultracompact high-sensitivity biochemical sensors utilizing high-Q PhC nanobeam cavities.