Compact spectrometers and instruments including them
A spectrometer with a Schmidt reflector is described. The spectrometer may include a Schmidt corrector and a dispersive element as separate components. Alternatively, the Schmidt corrector and dispersive element may be combined into a single optical component. The spectrometer may further include a field-flattener lens.
1. An optical spectrometer comprising:
an off-axis telescope comprising a reflective corrector;
an Echelle grating configured to receive light from a light source before the off-axis telescope receives any of the light from the light source; and
a detector optically coupled to the off-axis telescope and configured to receive, via a light path between the off-axis telescope and the detector, light reflected by the off-axis telescope, wherein light incident on the detector comprises a plurality of wavelengths that are spatially separated by the Echelle grating.
2. The optical spectrometer of claim 1 , wherein the light path between the off-axis telescope and the detector is unobstructed.
3. The optical spectrometer of claim 1 , wherein the light path between the off-axis telescope and the detector is unobscured.
4. The optical spectrometer of claim 1 , wherein the off-axis telescope comprises an off-axis Schmidt telescope.
5. The optical spectrometer of claim 1 , wherein the reflective corrector comprises a Schmidt corrector.
6. The optical spectrometer of claim 1 , wherein the reflective corrector comprises a mirror.
7. The optical spectrometer of claim 1 , wherein the reflective corrector comprises a spherical mirror.
8. The optical spectrometer of claim 1 , wherein the off-axis telescope comprises a dispersive element.
9. The optical spectrometer of claim 1 , wherein:
the off-axis telescope comprises a prism; and
the reflective corrector comprises an aspheric surface on a face of the prism.
10. The optical spectrometer of claim 1 , wherein:
the off-axis telescope comprises a prism; and
the reflective corrector is separate and independent of the prism.
11. The optical spectrometer of claim 1 , wherein the off-axis telescope comprises a double-pass reflective prism.
12. The optical spectrometer of claim 1 , further comprising a field flattening lens positioned in the light path and optically coupled to the off-axis telescope and the detector.
13. The optical spectrometer of claim 1 , further comprising:
an aperture; and
a collimator optically coupled to the aperture;
wherein the Echelle grating is optically coupled to the collimator.
14. A single-pass optical spectrometer comprising:
an Echelle grating;
an off-axis Schmidt telescope comprising a reflective Schmidt corrector configured to reflect light along an unobstructed light path; and
a detector optically coupled to the off-axis Schmidt telescope and configured to receive, via the unobstructed light path, the light reflected by the reflective Schmidt corrector, wherein light incident on the detector comprises a plurality of wavelengths that are spatially separated by the Echelle grating.
15. The single-pass optical spectrometer of claim 14 , wherein the off-axis Schmidt telescope comprises at least a portion of spherical mirror.
16. The single-pass optical spectrometer of claim 14 , wherein the off-axis Schmidt telescope comprises a dispersive element, and wherein the dispersive element comprises:
a prism;
a double-pass prism;
a reflective grating;
a grism; or
a cross-disperser.
17. The single-pass optical spectrometer of claim 14 , wherein the reflective Schmidt corrector comprises an aspheric surface of a prism of the off-axis Schmidt telescope.
18. The single-pass optical spectrometer of claim 14 , wherein the reflective Schmidt corrector is separate and independent of a dispersive element of the off-axis Schmidt telescope.
19. The single-pass optical spectrometer of claim 14 , wherein the reflective Schmidt corrector comprises a double-pass reflective prism.
20. The single-pass optical spectrometer of claim 14 , wherein the detector is configured to detect at least one of visible light, ultraviolet light, or infrared light.