1c:I[419806,["/_next/static/chunks/bb923814e1f4d2e9.js","/_next/static/chunks/dd3ee9f5b7716ca6.js","/_next/static/chunks/4204a0ae82542ca8.js","/_next/static/chunks/30036bedc5269936.js","/_next/static/chunks/6e1aa89a642f40be.js","/_next/static/chunks/cd5e572bc3e4eb92.js","/_next/static/chunks/8ffd0b71567920d8.js","/_next/static/chunks/67ea6dfd21f16c5f.js","/_next/static/chunks/24eb4379f68013fd.js","/_next/static/chunks/b8cd775ffdf935bd.js","/_next/static/chunks/983103cd9eb7b428.js","/_next/static/chunks/d4ac9dcf27f6ff52.js","/_next/static/chunks/294b9525248c8e5f.js"],"default"] 1d:T4c7,Results of theoretical and experimental investigations are reported on the feasibility and the performance of a highly sensitive and stable `standardized' sensing pad suitable for integration into a great variety of miniature hybrid and monolithic integrated optical sensors for biochemical and clinical analysis. The basic type of sensing pad structure consists of sensing layers immobilized at the surface of waveguiding films with a high refractive index deposited on low index substrates. As a simple biochemical model system for the sensing pad development, the binding of immunoglobulin (IgG) to immobilized protein A was chosen. Results obtained for TiO₂ waveguides at wavelengths of 633 nm and 785 nm show that these sensing pads feature very high sensitivities and an excellent stability, and that infrared laser diodes are adequate light sources. Resolutions and stabilities in the order of 1/4000 of a monolayer have been demonstrated by performing experiments for such chips in an input grating coupler configuration. Based on these results, surface coverage resolutions in the < 100 fg/mm² range have been estimated if such sensing pads were used in integrated optical interferometers.1e:T46a,Design considerations and experimental results are presented for the fabrication and characterization of grating couplers in gradient effective index waveguides used for realizing miniature integrated optical sensor modules. Hard dielectric substrates such as glass and fused silica have been structured by photolithographic techniques, while hot embossing has been used for the grating fabrication in plastic substrates. The gradient effective index waveguides were produced by shadow mask evaporation techniques in one single deposition step in a rotating substrate holder arrangement. Optical diffraction measurements, atomic force microscopy, and a newly developed method based on performing spatially resolved grating coupler resonance angle measurements are shown to be valuable tools for the characterization of the waveguides and the grating couplers. The experimental results indicate that the deposition of high-index waveguiding films such as Ta₂O₅ and TiO₂ on previously structured substrates is a viable technique for the cost-effective fabrication of integrated optical sensor chips.

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