Dual beam optical spectrograph

• US 5,757,483 A
• Filed: 08/06/1997
• Issued: 05/26/1998
• Est. Priority Date: 08/06/1997
• Status: Expired due to Fees

• Current Assignee: Stellarnet, Inc.
• Original Assignee: Stellarnet, Inc.
• Inventors: Pierce, William B. III
• Primary Examiner(s): EVANS, FANNIE L
• Application Number:
  US08/907,155
• Time in Patent Office: 293 Days
• Field of Search: 356/305, 356/319, 356/320, 356/326, 356/328, 356/334
• US Class Current: 356/305
• CPC Class Codes: G01J 3/18 using diffraction elements, e.g. grating gratings per se G02B

Abstract

A dual beam optical spectrograph includes a housing defining an internal chamber that is divided into two subchambers with a partition. A liner array detector such as a charge coupled detector array (CCD) is located within the chamber symmetrically to either side of the partition. Two light inputs are provided to either side of the partition between the CCD and a planar diffraction grating, and each light input is led through a concave collimating mirror, a planar diffraction grating, and a concave focusing mirror before light impinges upon the CCD. The inventive spectrograph is capable of providing synoptic data since both optical channels are captured simultaneously. The housing can be mounted on an adapter for an IBM compatible printed circuit board.

Claims

1. A spectrograph, comprising:

a) a housing with outer walls defining an inner chamber divided into two subchambers by a partition;

b) each subchamber having a light input;

c) each subchamber containing at least one concave collimating mirror adapted to direct light from said light input onto a planar diffraction grating from which the light is reflected to a concave focusing mirror and then onto a single contiguous light detector means; and

d) the light input in each subchamber is located between the planar grating and the light detector means.

2. The spectrograph of claim 1, wherein each light input comprises an optical fiber coupling.

3. The spectrograph of claim 1, wherein said light detector means comprises a single linear array light detector simultaneously serving both subchambers.

4. The spectrograph of claim 3, wherein said linear array light detector consists of a CCD array or a photodiode array.

5. The spectrograph of claim 1, wherein said planar diffraction grating operates within a range of 200-450 nm.

6. The spectrograph of claim 1, wherein said planar diffraction grating operates within a range of 350-850 nm.

7. The spectrograph of claim 1, wherein said planar diffraction grating operates within a range of 500-1000 nm.

8. A spectrograph, comprising:

a) a housing with outer walls defining an inner chamber divided into two subchambers by a partition;

b) each subchamber having a light input;

c) each subchamber containing a concave collimating mirror followed by a planar diffraction grating followed by a concave focusing mirror adapted to reflect light from said light input onto a single linear array light detector symmetrically disposed in said chamber with respect to said partition; and

d) the light input in each subchamber located between the planar diffraction grating and the linear array light detector.

9. The spectrograph of claim 8, wherein each light input comprises an optical fiber coupling.

10. The spectrograph of claim 8, wherein said planar diffraction grating operates within a range of 200-450 nm.

11. The spectrograph of claim 8, wherein said planar diffraction grating operates within a range of 350-850 nm.

12. The spectrograph of claim 8, wherein said planar diffraction grating operates within a range of 500-1000 nm.

13. The spectrograph of claim 8, wherein said housing is made from aluminum.

14. The spectrograph of claim 8, wherein said planar diffraction grating has about 600-1800 lines/mm.

15. The spectrograph of claim 8, wherein the linear array light detector is a CCD array.

16. The spectrograph of claim 8, wherein the linear array light detector is a photodiode array.

17. The spectrograph of claim 8, wherein the housing is made from a low coefficient of thermal expansion microcomposite material.

18. The spectrograph of claim 8, wherein the housing is mounted on a plug-in card for an IBM compatible printed circuit board.