A sensor (200, 900) comprising an illuminator (212, 500, 804, 832, 858, 904), a receiver (216, 400, 420, 460, 480, 808, 836, 862, 924) and an analyzer (240) for detecting and identifying an analyte having a characteristic absorption band that is present in a sample region (208, 812, 824, 874, 922). The illuminator includes an illumination source (220) for illuminating the sample region with spectral energy across at least a portion of the characteristic absorption band. The receiver includes a detector (228, 404, 424, 460, 484, 866, 928) for sensing predetermined portions of the spectral energy band and for creating a sample spectral data vector (236). The analyzer uses the spectral data vector and known characteristic data to detect and identify the analyte.