A scattering spectroscopy apparatus, system and method employ guided mode resonance (GMR) and a GMR grating. The apparatus includes a GMR grating having a subwavelength grating, and an optical detector configured to receive a portion of a scattered signal produced by an interaction between an excitation signal and an analyte associated with a surface of the GMR grating. A propagation direction of the received portion of the scattered signal is substantially different from a propagation direction of a GMR-coupled portion of the excitation signal within the GMR grating. The system includes the apparatus and an optical source. The method includes exciting a GMR in a GMR grating, interacting a GMR-coupled portion of the excitation signal with an analyte to produce a scattered signal and detecting a portion of the scattered signal.