Abstract: A spectrometer system comprises (i) a slab waveguide characterized as an index of refraction higher than a surrounding medium, and having front surface and a rear surface opposite thereto, the front surface including a input portion for accepting optical radiation, a diffractor portion and an exit portion, (ii) a diffraction grating disposed on said diffractor portion of said front surface, (iii) a detector array aligned adjacent to the exit portion, and (iv) a mirror coated on the rear surface of the waveguide. Radiation transmitted within the waveguide from the input portion is reflected and collimated by the mirror to the granting. Light diffracted from the grating is dispersed to the mirror and reflected toward and through the exit portion and onto the array.