Circle-to-line interferometer optical system

• US 4,893,003 A
• Filed: 09/19/1988
• Issued: 01/09/1990
• Est. Priority Date: 09/19/1988
• Status: Expired due to Term

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: University of Michigan
• Inventors: Hays, Paul B.
• Primary Examiner(s): Westin, Edward P.
• Assistant Examiner(s): Shami, Khaled
• Application Number:
  US07/246,096
• Time in Patent Office: 477 Days
• Field of Search: 250/216, 356/616, 356/630
• US Class Current: 250/216
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G01J 3/2803 using photoelectric array detector

Abstract

An optical system employs an internally conical reflector for converting circular fringe information, such as that which is produced by a Fabry-Perot Interferometer, into linear information whereby the reflected light can be received by conventional linear array detectors, such as charge coupled device which are used in spectroscopic analysis. The azimuthal angle of the detected circular fringe pattern is reduced with the use of a tele-kaleidoscope having a predetermined arrangement of mirrors. Electromagnetic energy which is issued from the interferometer is propagated substantially along the conical axis of the cone of which the reflector forms a segment, and is reflected and focused substantially onto a line in the vicinity of the conical axis, where the linear detector is situated. In a preferred embodiment, the apex of the cone is situated where the conical axis intersects the focal plane of the circular fringe pattern.

Claims

1. An optical system for converting information in the form of a circular ring of electromagnetic radiation to a linear form, the optical system comprising:

reflector means having a reflective surface configured at least in part as an internal conical surface, for receiving and reflecting the electromagnetic radiation; and

linear detector means arranged to receive the electromagnetic radiation reflected by said reflective surface of said reflector means.

2. The optical system of claim 1 wherein said internal conical surface of said reflector means is arranged at 45°

with respect to a central axis.

3. The optical system of claim 2 wherein said linear detector means is arranged in the vicinity of said central axis for receiving a linear form of the electromagnetic radiation.

4. The optical system of claim 2 wherein the electromagnetic radiation is propagated in a direction substantially parallel to said central axis and has a focal plane transverse to said central axis, said internal conical surface having a vertex on said central axis.

5. The optical system of claim 4 wherein said vertex of said internal conical surface is substantially coincident with the focal plane of the electromagnetic radiation.

6. The optical system of claim 1 wherein said linear detector means comprises a charge coupled device for producing an electric signal responsive to the electromagnetic radiation.

7. The optical system of claim 1 wherein there is further provided kaleidoscopic means for reducing an azimuthal angle of the electromagnetic radiation.

8. The optical system of claim 7 wherein said kaleidoscopic means comprises a 90°

tele-kaleidoscope.

9. An optical system for converting information in the form of a circular ring of electromagnetic radiation to a linear form, the optical system comprising:

kaleidoscopic means having a plurality of reflector members for determining a segment of the circular ring of the electromagnetic radiation;

conical reflector means having a reflective surface configured substantially as an internal conical surface, for receiving and reflecting said segment of the circular ring of the electromagnetic radiation; and

linear detector means arranged to receive the electromagnetic radiation reflected by said reflective surface of said reflector means.

10. The optical system of claim 9 wherein said reflector members of said kaleidoscopic means are arranged at 90°

with respect to one another.

11. The optical system of claim 9 wherein said reflective surface of said conical reflector means is configured at least in part to be oriented at 45°

with respect to a central axis of said kaleidoscopic means.

12. The optical system of claim 11 wherein said linear detector means is arranged in the vicinity of said central axis for receiving a focused linear form of the electromagnetic radiation from said conical reflector means.

13. A method of converting circular interferometric information into electrical information, the method comprising the steps of:

reflecting a light signal containing the circular interferometric information from a conical reflector; and

receiving said reflected light signal at a linear detector which converts said reflected light signal into a corresponding electrical signal.

14. The method of claim 13 wherein prior to performing said step of reflecting there is provided the further step of sectoring the light signal containing the circular interferometric information whereby the circular interferometric information is contained in a sector of a circle.

15. The method of claim 14 wherein said step of sectoring is performed using a tele-kaleidoscope.

16. The method of claim 13 wherein said detector at which said reflected light signal is received is a charge coupled device.

17. The method of claim 13 wherein said conical reflector is arranged at an angle of approximately 45°

with respect to a direction of propagation of said light signal.