Method and apparatus for multiplexed fabry-perot spectroscopy

Patent metadata

Field	Value
Publication number	US-9304040-B2
Application number	US-201414282067-A
Country	US
Kind code	B2
Filing date	May 20, 2014
Priority date	May 21, 2013
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

A method of optical spectroscopy and a device for use in optical spectroscopy. The device includes a substrate, and a plurality of etalon cavities affixed to or coupled to the substrate. A signal is received from a Fabry-Perot interferometer. The signal is sampled using the device according to a generalized Nyquist-Shannon sampling criterion. The signal is sampled using the device according to a phase differential criterion for wave number resolution. An input spectrum for the signal is reconstructed based on the signal sampled according to the generalized Nyquist-Shannon sampling criterion and the signal sampled according to the phase differential criterion for wave number resolution.

First claim

What is claimed as new and desired to be protected by Letters Patent of the United States is:

1. A device comprising:
a substrate; and
a plurality of etalon cavities one of affixed to and coupled to said substrate, said plurality of etalon cavities comprising a plurality of cavity thicknesses;
wherein each etalon cavity of said plurality of etalon cavities comprises a respective height value, said each etalon cavity of said plurality of etalon cavities having an associated next highest height value etalon cavity of said plurality of etalon cavities, said associated next highest height value etalon cavity of said plurality of etalon cavities comprising a next highest height value, said each etalon cavity of said plurality of etalon cavities having an associated next lowest height value etalon cavity of said plurality of etalon cavities, said associated next lowest height value etalon cavity of said plurality of etalon cavities comprising a next lowest height value, a difference between the next highest height value and the respective height value satisfying a generalized Nyquist-Shannon sampling criterion, a difference between the respective height value and the next lowest height value satisfying the generalized Nyquist-Shannon sampling criterion, and
wherein said plurality of cavity thicknesses comprises a maximum height value and a minimum height value, a difference between said maximum height value and minimum height value is at least an overall height range, said overall height range satisfying a phase differential criterion for wavenumber resolution.

2. The device according to claim 1 , wherein said substrate comprises a detector; and
wherein said generalized Nyquist-Shannon sampling criterion comprises:

δ
≤

1

4
⁢
Fn
⁢

⁢

σ
max

,

where δ is a step size, F is a cavity finesse, n is a cavity refractive index, and σ max is a maximum vacuum wavenumber to which said detector is sensitive.

3. The device according to claim 1 , wherein said phase differential criterion for wavenumber resolution comprises:

d
r

≤

1

2
⁢
Fn
⁢

⁢
Δ
⁢

⁢
σ

,

where d, is said overall height range, F is a cavity finesse, n is a refractive index of a cavity, and Δσ is a vacuum wavenumber resolution of the device.

4. The device according to claim 1 , wherein said plurality of etalon cavities comprises one of an evenly spaced plurality of etalon cavities and an unevenly spaced plurality of etalon cavities.

5. The device according to claim 1 , wherein said substrate comprises one of a detector and an image sensor.

6. The device according to claim 5 , wherein said image sensor comprises a two-dimensional focal plane array,
wherein said detector comprises one of a point detector, a linear array detector, and a two-dimensional array detector.

7. The device according to claim 1 , wherein said each etalon cavity of said plurality of etalon cavities comprises two mirrors sandwiching a dielectric material.

8. The device according to claim 7 , wherein each mirror of said two mirrors comprise one of a flat, reflective surface and a reflective coating.

9. The device according to claim 7 , wherein each mirror of said two mirrors comprises a material boundary wherein a reflection is due to differences in refractive index.

10. The device according to claim 7 , wherein said plurality of etalon cavities comprise a plurality of Fabry-Perot cavities.

11. The device according to claim 1 , wherein said plurality of etalon cavities comprises a staircase cross-sectional profile.

12. The device according to claim 1 , further comprising imaging optics, a detector, and a scanner.

13. The device according to claim 12 , wherein said imaging optics comprise one of patterned illumination, at least one diffractive optical element, at least one aperture assembly, at least one spatial light modulator, at least one micro-mirror array, at least one lens, and at least one mirror.

14. The device according to claim 12 , wherein said scanner comprises one of a fast scanning mirror scanner, a platform-motion scanner, a moveable diffractive optical element, a moveable refractive optical element, at least one translation stage providing motion for said imaging sensor, at least one rotation stage providing motion for said imaging sensor, and a gimbalized scanner.

15. The device according to claim 12 , wherein said detector comprises one of a point detector, a linear array detector, and a two-dimensional array detector.

Assignees

• Yetzbacher Michael K
• Miller Christopher W
• Deprenger Michael J
• Boudreau Andrew J
• Us Navy

Inventors

• Yetzbacher Michael K
• Miller Christopher W
• Deprenger Michael J
• Boudreau Andrew J

Classifications

• G01J3/45

  Interferometric spectrometry · CPC title

• G01J3/021

  using plane or convex mirrors, parallel phase plates, or particular reflectors · CPC title

• G01J3/26 Primary

  using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters · CPC title

• G01N21/45

  using interferometric methods; using Schlieren methods · CPC title

• G01N21/41

  Refractivity; Phase-affecting properties, e.g. optical path length (G01N21/21 takes precedence) · CPC title