We present the design, fabrication and optical investigation of photonic crystal (PhC) nanocavity drop filters for use as optical biosensors. The resonant cavity mode wavelength and Q-factor are studied as a function of the ambient refractive index and as a function of adsorbed proteins (bovine serum albumin) on the sensor surface. Experiments were performed by evanescent excitation of the cavity mode via a PhC waveguide. This in turn is coupled to a ridge waveguide that allows the introduction of a fluid flow cell on a chip. A response of ∂λ/∂c=(4.54±0.66)×105 nm/M is measured leading to a measured detection limit as good as fg or pg/mm2in the sensitive area.
- optical biosensor
- photonic crystal
Dorfner, D., Zabel, T., Hürlimann, T., Hauke, N., Frandsen, L. H., Rant, U., Abstreiter, G., & Finley, J. (2009). Photonic crystal nanostructures for optical biosensing applications. Biosensors and Bioelectronics, 24(12), 3688-3692. https://doi.org/10.1016/j.bios.2009.05.014