Optical devices having a wavelength-tunable dispersion assembly that has a volume dispersive diffraction grating

A spectrometer, comprising:

• a source of illumination radiation having a plurality of spectral wavelengths;
• a beamsplitter disposed in an optical path of said source of illumination radiation;
• a spectrograph disposed in a path of radiation from a sample illuminated by illumination radiation from said source of illumination radiation;
• an optical bandpass filter disposed in said optical path of said source of illumination radiation;
• and
• a rejection filter disposed in said path of radiation from said sample between said sample and said spectrograph,
• wherein at least one of said beamsplitter, said spectrograph, said optical bandpass filter, and said rejection filter comprises a wavelength-tunable dispersion assembly comprising a mirror and a volume-dispersion diffraction grating, said mirror having a substantially fixed orientation and displacement with respect to said volume-dispersion diffraction grating, and
• wherein said volume-dispersion diffraction grating and said mirror are movable together substantially as a unit.

A spectrograph, comprising:

• an input aperture;
• a detector having a substantially fixed position and a substantially fixed orientation with respect to said input aperture;
• and
• a wavelength-tunable dispersion assembly disposed between said input aperture and said detector, said wavelength-tunable dispersion assembly comprising a mirror, a volume-dispersion diffraction grating and a support stage, said mirror having a substantially fixed orientation and displacement with respect to said volume-dispersion diffraction grating, said support stage has a surface to which said volume-dispersion diffraction grating and said mirror are mounted, said support stage being rotatable about an axis of rotation substantially orthogonal to said surface of said support stage,
• wherein said volume-dispersion diffraction grating said mirror are movable together substantially as a unit with respect to said input aperture and said detector to effect a change in wavelengths of light directed to said detector after passing through said input aperture to said wavelength-tunable dispersion assembly.