We present a multi-modality optical sensing platform employing integrated Vertical Cavity Surface Emitting Lasers
(VCSELs), photodetectors, and filters suitable for portable, real-time analyte detection in aqueous environments.
Fluorescence and refractive index sensors designed to utilize visible and near-infrared VCSELs for low background
absorption from analyte delivery fluids are described. We demonstrate in vitro fluorescence sensing of Cy5.5 dye with a
detection sensitivity of 5 nM and photonic crystal slab refractive index sensing with tunable GaAs-based 670 nm
VCSELs. This compact, parallel sensor architecture enables multiplexed, cost-effective on-chip biosensing.
We present the optical characterization of an all-dielectric photonic crystal (PC)-based guided resonance filter sensitive to index-of-refraction changes in aqueous solutions. Spectral peak width was found to be 9.8 and 4.4 nm around 816 nm (water media), corresponding to a quality factor Q of 83 and 181, respectively. A spectral shift of peak wavelength with index change of 130 nm/RIU was observed for bulk fluid experiments. Measured peak shift (&Dgr;&lgr;=0.2nm) corresponds to a detectable index change &Dgr;n=1.5×10<sup>-3</sup>.
We present the design, simulation, and fabrication of an all-dielectric photonic crystal-based nano-sensor that detects index of refraction changes in aqueous solutions. The photonic crystal structure is designed for incorporation with an optical readout module that includes a light source, detector, and micro-optics to form a miniature integrated nanosensor. This enables reduced cost, small sample volume, and increased speed and parallelism desirable for high throughput analysis in medical diagnostics.