Linearized variable-dispersion spectrometers and related assemblies

A wavenumber linearized spectrometer, the spectrometer comprising:

• an input configured to receive broadband electromagnetic radiation from an external source;
• collimating optics configured to collimate the received electromagnetic radiation;
• a dispersive assembly comprising at least three elements, the at least three elements including:
• a first diffractive element arranged to receive the collimated electromagnetic radiation wavefront and to disperse the collimated input radiation wavefront into a wavenumber-dependent angular spectrum;
• a second diffractive element arranged to receive an electromagnetic radiation wavefront, said wavefront having been first dispersed into a wavenumber-dependent angular spectrum by the action of at least the first diffractive element, and arranged to disperse the input wavenumber-dependent angular spectrum into an output wavenumber-dependent angular spectrum different from the incident spectrum;
• and
• an imaging lens assembly configured to receive an electromagnetic radiation wavefront, said wavefront having been first dispersed into a wavenumber-dependent angular spectrum by the action of at least the first diffractive element, and configured to transform an input wavenumber-dependent angular spectrum into an output wavenumber-dependent angular spectrum different from the incident spectrum, the imaging lens assembly including a means for pincushion distortion correction;
• and
• a detector array positioned to receive at least a portion of the dispersed spectrum of electromagnetic radiation after passing through an optical path that includes the set of collimating optics, a first diffractive element, a second diffractive element and an imaging lens assembly,
• wherein the dispersive actions of at least the first diffractive element, the second diffractive element and the imaging lens assembly cooperate to disperse a substantially collimated source of broadband electromagnetic radiation such that the wavenumber increment is substantially constant with respect to spatial increment along the detector array.

A spectrometer, the spectrometer comprising:

• an input configured to receive broadband electromagnetic radiation from an external source;
• collimating optics configured to collimate the received electromagnetic radiation;
• a dispersive assembly comprising at least three elements, the at least three elements including:
• a first diffractive element arranged to receive the collimated electromagnetic radiation wavefront and to disperse the collimated input radiation wavefront into a wavenumber-dependent angular spectrum;
• a second diffractive element arranged to receive an electromagnetic radiation wavefront, said wavefront having been first dispersed into a wavenumber-dependent angular spectrum by the action of at least the first diffractive element, and arranged to disperse the input wavenumber-dependent angular spectrum into an output wavenumber-dependent angular spectrum different from the incident spectrum;
• and
• a refractive element configured to receive an electromagnetic radiation wavefront, said wavefront having been first dispersed into a wavenumber-dependent angular spectrum by the action of at least the first diffractive element, and configured to transform an input wavenumber-dependent angular spectrum into an output wavenumber-dependent angular spectrum different from the incident spectrum;
• and
• a detector array positioned to receive at least a portion of the dispersed spectrum of electromagnetic radiation after passing through an optical path that includes the set of collimating optics, a first diffractive element, a second diffractive element and a refractive element,
• wherein the dispersive actions of at least a first diffractive element, a second diffractive element and a refractive element cooperate to disperse a substantially collimated source of broadband electromagnetic radiation such that wavenumber increment is substantially constant with respect to spatial increment along the detector array.