Finite grating depth effects for integrated optical sensors with high sensitivity

Results of theoretical calculations are related to experimental observations for highly resonant waveguide structures. Such structures provide very high sensitivities for the optical characterization of chemical and biochemical sensing layers by means of integrated optical sensor chips. Although very shallow grating couplers in the nanometer range have to be employed, rigorous solution of Maxwell's equations is required for a reliable determination of their optical properties. Examples optimized for practical applications are discussed in detail. The results are important for the optical characterization and reliable signal interpretation of such sensor chips.