# US 2023/0408337 A1 · Quadrilateral common-path time-modulated interferometric spectral imaging device and method

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- Number: US 2023/0408337 A1
- Document ID: US20230408337A1
- Status: Published application
- Kind: A1
- Application number: 18/320,172
- Filed: 2023-05-18
- Published: 2023-12-21
- Earliest claimed: 2022-06-13
- Assignees: Wuhan University
- Applicants: Wuhan University
- Inventors: Ruyi WEI
- Web page: https://patentgrep.com/patent/US20230408337A1

## CPC

- G01J 3/4535: {Devices with moving mirror (G01J3/4532 takes precedence)}
- G01J 3/0205: {Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows}
- G01J 3/0208: {using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction}
- G01J 3/021: {using plane or convex mirrors, parallel phase plates, or particular reflectors}
- G01J 3/06: Scanning arrangements {arrangements for order-selection}
- G01J 3/2823: {Imaging spectrometer}
- G01J 3/0237: {Adjustable, e.g. focussing}
- G01J 2003/062: {motor-driven}
- G01J 2003/064: {Use of other elements for scan, e.g. mirror, fixed grating}
- G01J 2003/4538: {Special processing}
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)

## Abstract

The present invention belongs to the field of optical technology, disclosing a quadrilateral common-path time-modulated interferometric spectral imaging device and method. The present invention sets up a moving mirror scanning mechanism in a quadrilateral common path interferometer for generating optical path differences that vary with time, so that the quadrilateral common-path time-modulated interferometric spectral imaging device operates in the staring observation mode. The invention can make the quadrilateral common-path time-modulated interferometric spectral imaging device not only retain the advantages of common optical path spectroscopic technology, but also obtain high spectral resolution.

## Claims

### Claim 1

A quadrilateral common-path time-modulated interferometric spectral imaging device comprising a quadrilateral common-path interferometer, the quadrilateral common-path interferometer has an asymmetric structure, and the quadrilateral common-path interferometer is provided with a moving mirror scanning mechanism for generating time-varying optical path difference, and the quadrilateral common-path time-modulated interferometric spectral imaging device works in a staring observation mode;
the quadrilateral common-path interferometer comprises a first optical path adjustment module and a second optical path adjustment module; the first optical path adjustment module and the second optical path adjustment module are combined to constitute the moving mirror scanning mechanism, the first optical path adjustment module and the second optical path adjustment module are placed in two arms of the interferometer, and the two arms respectively produce a first optical path and a second optical path, a combination of the first optical path and the second optical path forms optical path difference changes from −L to 0 and then from 0 to +L, where L is a maximum optical path difference,
wherein the quadrilateral common-path interferometer further comprises a semi-transparent semi-reflective beam splitter, a first planar mirror, a second planar mirror, and a third planar mirror;
a target light is incident to the quadrilateral common-path interferometer, which is divided into a first transmitted beam and a first reflected beam after passing through the semi-transparent semi-reflective beam splitter; the first transmitted beam returns to the semi-translucent semi-reflective beam splitter again after reflecting from the first plane mirror, the second plane mirror, and the third plane mirror and passing through the first optical path adjustment module, and is divided into a second transmitted beam and a second reflected beam by the semi-transparent semi-reflective beam splitter; the first reflected beam returns to the semi-transparent semi-reflective beam splitter again after reflecting from the first plane mirror, the second plane mirror, and the third plane mirror, and passing through the second optical path adjustment module, and is divided into a third transmitted beam and a third reflected beam by the semi-transparent semi-reflective beam splitter; the second reflected beam and the third transmitted beam exit in a first direction, and the second transmitted beam and the third reflected beam exit in a second direction,
wherein the first transmitted beam and the first reflected beam are incident on the first planar mirror at different positions, and the first transmitted beam and the first reflected beam are incident on the second planar mirror at different positions.

### Claim 2

(canceled)

### Claim 3 (depends on 1)

The quadrilateral common-path time-modulated interferometric spectral imaging device according to claim 1, wherein one of the first optical path adjustment module and the second optical path adjustment module is a moving mirror, and the other optical path adjustment module is a fixed mirror; the optical path adjustment module as the moving mirror includes an optical path adjustment device and a motor, the optical path adjustment module moves under the drive of the motor; the path adjustment module as the fixed mirror includes only an optical path adjustment device.

### Claim 4 (depends on 3)

The quadrilateral common-path time-modulated interferometric spectral imaging device according to claim 3, wherein the optical path adjustment device in the optical path adjustment module as a moving mirror comprises a first prism and a second prism, and the optical path adjustment device in the optical path adjustment module as the fixed mirror comprises a third prism and a fourth prism; an exit surface after a beam passing through any one of the first prism, the second prism, the third prism, and the fourth prism is parallel to an incident surface; the first prism and the second prism rotate under the drive of the motor, and a rotation axis of the motor is perpendicular to a propagation direction of the beam; attitudes of the third prism and the fourth prism have angles tilt relative to a perpendicular incident surface of the beam, which is used to compensate for an zero dispersion effect and increase an zero-crossing optical path difference position.

### Claim 5 (depends on 1)

The quadrilateral common-path time-modulated interferometric spectral imaging device according to claim 1, wherein the first optical path adjustment module and the second optical path adjustment module are moving mirrors, the first optical path adjustment module comprises a first optical path adjustment device and a first motor, and the second optical path adjustment module comprises a second optical path adjustment device and a second motor; the first optical path adjustment device moves under the drive of the first motor, and the second optical path adjustment device moves under the drive of the second motor.

### Claim 6 (depends on 5)

The quadrilateral common-path time-modulated interferometric spectral imaging device according to claim 5, wherein a motion mode of the moving mirror is one of a rotation, a swing, and a linear motion.

### Claim 7 (depends on 1)

The quadrilateral common-path time-modulated interferometric spectral imaging device according to claim 1, further comprises: a convergence module, a detection acquisition module and a signal processing module; a target surface of the detection acquisition module is located on a back focal plane of the convergence module, and the signal processing module is connected with the detection acquisition module; the convergence module is configured to form interference from the beam exited by the quadrilateral common-path interferometer, and image it onto the detection acquisition module; the detection acquisition module is configured to sample and collect an interference fringe signal at different moments, and convert it into an electrical signal to obtain detection information; the signal processing module is configured for spectral restoration according to the detection information to obtain a spectral information.

### Claim 8 (depends on 1)

The quadrilateral common-path time-modulated interferometric spectral imaging device according to claim 1, further comprises: a pre-module; the pre-module comprises a converging lens, an aperture and a collimating lens disposed sequentially along an optical path; the target light passes through the pre-module and becomes a parallel light and is incident to the quadrilateral common-path interferometer.

### Claim 9 (depends on 1)

A quadrilateral common-path time-modulated interferometric spectral imaging method, wherein the quadrilateral common-path time-modulated interferometric spectral imaging device is used to achieve the quadrilateral common-path time-modulated interferometric spectral imaging device according to claim 1, by setting the moving mirror scanning mechanism for generating the time-varying optical path difference in the quadrilateral common-path interferometer, so that the quadrilateral common-path time-modulated interferometric spectral imaging device works in the staring observation mode.

### Claim 10 (depends on 9)

The quadrilateral common-path Fourier Transform spectroscopy imaging method according to claim 9, comprises the following steps:
Step 1: a target light becomes a parallel light after passing through a pre-module and is incident to the quadrilateral common-path interferometer;
Step 2: the parallel light is divided into a first transmitted beam and a first reflected beam by a semi-transparent semi-reflective beam splitter; the first transmitted beam returns to the semi-transparent semi-reflective beam splitter again after reflecting from a first plane mirror, a second plane mirror, and a third plane mirror and passing through the first optical path adjustment module, and is divided into a second transmitted beam and a second reflected beam by the semi-transparent semi-reflective beam splitter; the first reflected beam reflects from the first plane mirror, the second plane mirror, and the third plane mirror and passes through the second optical path adjustment module and returns again to the semi-translucent semi-reflective beam splitter, and is divided into a third transmitted beam and a third reflected beam by the semi-transparent semi-reflective beam splitter; the second reflected beam and the third transmitted beam are emitted in a first direction, and the second transmitted beam and the third reflected beam are emitted in a second direction;
Step 3: the beam exited by the quadrilateral common-path interferometer is formed into interference through a convergence module, and imaged to a detection acquisition module;
Step 4: through the detection acquisition module to sample and collect interference fringe signals at different moments, and convert into electrical signals to obtain a detection information;
Step 5: a spectral restoration is carried out according to the detection information through a signal processing module to obtain a spectral information.