Abstract: Fluorescence based sensing systems and methods that exploit xerogels are provided. Embodiments of the invention encompass a sensing system that includes: an optical excitation source emitting over a first predetermined wavelength range and capable of analog modulation over a predetermined frequency range; a sensor including a gel substrate incorporating within its matrix a receptor for molecular recognition of an analyte and a luminophore for signaling a recognition event relating to the analyte, the luminophore emitting an optical signal over a second predetermined wavelength range; a detection circuit including an optical detector for receiving the optical signal emitted by the luminophore and generating a photocurrent in dependence thereof; an excitation circuit that generates an analog signal for modulating the optical excitation source in dependence upon a digital control; and a read circuit for receiving the photocurrent and generating a digital output.