Monolithic infrared spectrometer apparatus and methods

A spectrometer comprising:

• a. an optical waveguide characterized by an index of refraction greater than a surrounding medium, said optical waveguide being disposed about a reference plane defined by first and second intersecting axes, said first and second axes being mutually perpendicular,
• said waveguide having a planar top surface and a planar bottom surface, said top surface and said bottom surface being parallel to said reference plane, and
• said waveguide having a lateral surface extending in the direction of a third axis perpendicular to said first and second axes, between said top surface and said bottom surface,
• said lateral surface including a planar front surface perpendicular to said first axis and parallel to said second axis, and including a cylindrical rear surface opposite said front surface and disposed about an axis parallel to said third axis,
• wherein said front surface includes an input portion, a diffractor portion and a detector portion, said input portion, diffractor portion and exit portion being spread apart in the direction of said second axis,
• b. an optical reflector disposed adjacent to said rear surface, said reflector being adopted to reflect incident light in said waveguide,
• c. a diffraction granting disposed on said diffractor portion,
• d. a detector array adjacent to said exit portion and extending in a direction at least in part in the direction of said second axis,
• wherein said rear surface has a selected radius of curvature and spacing from said input portion whereby incident light focused on said input portion propagates in said waveguide to said reflector whereupon said light is reflected toward said diffractor portion, and
• wherein said rear surface has a selected radius of curvature and spacing from said detector portion whereby light propagating from said reflector and incident on said diffractor portion is diffracted and reflected toward said reflector whereupon said light is reflected toward said exit portion and passes therethrough to be incident on said detector.