Optical device for improved wavelength resolution and wavelength accuracy

Patent metadata

Field	Value
Publication number	US-9863810-B2
Application number	US-201614986861-A
Country	US
Kind code	B2
Filing date	Jan 4, 2016
Priority date	Jan 7, 2015
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

An optical device includes: a diffraction grating; a depolarization plate containing a birefringent material to eliminate polarization dependency of the diffraction grating; and an optical corrector configured to optically correct diffraction angle deviation of diffracted light due to diffraction at the diffraction grating. The optical corrector may be configured to bend back the diffracted light diffracted by the diffraction grating to re-emit the light to the diffraction grating.

First claim

What is claimed is:

1. An optical device comprising:
a diffraction grating;
a depolarization plate containing a birefringent material to eliminate polarization dependency of the diffraction grating; and
an optical corrector configured to optically correct diffraction angle deviation of diffracted light due to diffraction at the diffraction grating.

2. The optical device according to claim 1 , wherein
the optical corrector is configured to bend back the diffracted light diffracted by the diffraction grating to re-emit the light to the diffraction grating.

3. The optical device according to claim 1 , wherein
the optical corrector is configured to invert a positional relationship of the diffracted light in a diffusion direction without changing a positional relationship of the diffracted light in a non-diffusion direction.

4. The optical device according to claim 2 , wherein
the optical corrector is configured to invert a positional relationship of the diffracted light in a diffusion direction without changing a positional relationship of the diffracted light in a non-diffusion direction.

5. The optical device according to claim 1 , wherein
the optical corrector includes
a first lens configured to condense the diffracted light diffracted by the diffraction grating,
a second lens configured to convert the light, diffusing after being condensed by the first lens, into parallel light,
a first mirror configured to reflect the light emitted from the second lens such that an optical path thereof is bent at a right angle,
a second mirror configured to reflect the light reflected by the first mirror such that the optical path thereof is bent at the right angle,
a third lens configured to condense the light reflected by the second mirror, and
a fourth lens configured to convert the light, diffusing after being condensed by the third lens, into parallel light to emit the parallel light to the diffraction grating.

6. The optical device according to claim 2 , wherein
the optical corrector includes
a first lens configured to condense the diffracted light diffracted by the diffraction grating,
a second lens configured to convert the light, diffusing after being condensed by the first lens, into parallel light,
a first mirror configured to reflect the light emitted from the second lens such that an optical path thereof is bent at a right angle,
a second mirror configured to reflect the light reflected by the first mirror such that the optical path thereof is bent at the right angle,
a third lens configured to condense the light reflected by the second mirror, and
a fourth lens configured to convert the light, diffusing after being condensed by the third lens, into parallel light to emit the parallel light to the diffraction grating.

7. The optical device according to claim 3 , wherein
the optical corrector includes
a first lens configured to condense the diffracted light diffracted by the diffraction grating,
a second lens configured to convert the light, diffusing after being condensed by the first lens, into parallel light,
a first mirror configured to reflect the light emitted from the second lens such that an optical path thereof is bent at a right angle,
a second mirror configured to reflect the light reflected by the first mirror such that the optical path thereof is bent at the right angle,
a third lens configured to condense the light reflected by the second mirror, and
a fourth lens configured to convert the light, diffusing after being condensed by the third lens, into parallel light to emit the parallel light to the diffraction grating.

8. The optical device according to claim 4 , wherein
the optical corrector includes
a first lens configured to condense the diffracted light diffracted by the diffraction grating,
a second lens configured to convert the light, diffusing after being condensed by the first lens, into parallel light,
a first mirror configured to reflect the light emitted from the second lens such that an optical path thereof is bent at a right angle,
a second mirror configured to reflect the light reflected by the first mirror such that the optical path thereof is bent at the right angle,
a third lens configured to condense the light reflected by the second mirror, and
a fourth lens configured to convert the light, diffusing after being condensed by the third lens, into parallel light to emit the parallel light to the diffraction grating.

9. The optical device according to claim 1 , wherein
the optical corrector includes
a concave mirror configured to convert incident light into parallel light to emit the parallel light to the diffraction grating and configured to reflect and condense the diffracted light diffracted by the diffraction grating,
a fifth lens configured to convert the light reflected by the concave mirror into parallel light,
a third mirror configured to reflect the light emitted from the fifth lens such that an optical path thereof is bent at a right angle,
a fourth mirror configured to reflect the light reflected by the third mirror such that the optical path thereof is bent at the right angle, and
a sixth lens configured to condense the light reflected by the fourth mirror to emit the condensed light to the concave mirror.

10. The optical device according to claim 2 , wherein
the optical corrector includes
a concave mirror configured to convert incident light into parallel light to emit the parallel light to the diffraction grating and configured to reflect and condense the diffracted light diffracted by the diffraction grating,
a fifth lens configured to convert the light reflected by the concave mirror into parallel light,
a third mirror configured to reflect the light emitted from the fifth lens such that an optical path thereof is bent at a right angle,
a fourth mirror configured to reflect the light reflected by the third mirror such that the optical path thereof is bent at the right angle, and
a sixth lens configured to condense the light reflected by the fourth mirror to emit the condensed light to the concave mirror.

11. The optical device according to claim 3 , wherein
the optical corrector includes
a concave mirror configured to convert incident light into parallel light to emit the parallel light to the diffraction grating and configured to reflect and condense the diffracted light diffracted by the diffraction grating,
a fifth lens configured to convert the light reflected by the concave mirror into parallel light,
a third mirror configured to reflect the light emitted from the fifth lens such that an optical path thereof is bent at a right angle,
a fourth mirror configured to reflect the light reflected by the third mirror such that the optical path thereof is bent at the right angle, and
a sixth lens configured to condense the light reflected by the fourth mirror to emit the condensed light to the concave mirror.

12. The optical device according to claim 4 , wherein
the optical corrector includes
a concave mirror configured to convert incident light into parallel light to emit the parallel light to the diffraction grating and configured to reflect and condense the diffracted light diffracted by the diffraction grating,
a fifth lens configured to convert the light reflected by the concave mirror into parallel light,
a third mirror configured to reflect the light emitted from the fifth lens such that an optical path thereof is bent at a right angle,
a fourth mirror configured to reflect the light reflected by the third mirror such that the optical path thereof is bent at the right angle, and
a sixth lens configured to condense the light reflected by

Assignees

• Yokogawa Electric Corp
• Yokogawa Test & Measurement Corp

Inventors

• Kaneko Tsutomu
• Kojima Manabu

Classifications

• G02B5/3083

  Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001) · CPC title

• G01J3/18 Primary

  using diffraction elements, e.g. grating (gratings per se G02B) · CPC title

• G01J3/0224

  using polarising or depolarising elements · CPC title

• G02B17/008

  Systems specially adapted to form image relays or chained systems · CPC title

• G01J3/0216

  using light concentrators or collectors or condensers · CPC title