# US 8,786,949 B2 · Method for polarizing terahertz electromagnetic wave using polarizer, and polarizer

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- Number: US 8,786,949 B2
- Document ID: US8786949B2
- Status: Granted
- Kind: B2
- Application number: 13/943,613
- Filed: 2013-07-16
- Published: 2013-11-14
- Granted: 2014-07-22
- Earliest claimed: 2011-11-16
- Assignees: Panasonic Corporation
- Applicants: Panasonic Corporation
- Inventors: Kohei Takahashi; Tsutomu Kanno; Akihiro Sakai; Yuka Yamada
- Web page: https://patentgrep.com/patent/US8786949B2

## CPC

- G02B 5/3083: {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)}
- B29D 11/00644: {polarizing}
- H01S 3/06712: {Polarising fibre; Polariser}
- G02B 1/02: made of crystals, e.g. rock-salt, semi-conductors (G02B1/08 takes precedence)
- H01Q 15/24: Polarising devices; Polarisation filters (H01Q15/12, H01Q15/22 take precedence)
- Y10S 359/90: Methods
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00)
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A method for polarizing an electromagnetic wave having a frequency of not less than 0.1 THz and not more than 0.8 THz using a polarizer includes steps (a) and (b). The step (a) includes preparing the polarizer. The polarizer includes: a sapphire single crystalline layer; and a CaxCoO2 crystalline layer. The CaxCoO2 crystalline layer is stacked on the sapphire single crystalline layer, a surface of the CaxCoO2 crystalline layer has a (100) plane orientation and the CaxCoO2 crystalline layer has a thickness of not less than 2 micrometers and not more than 20 micrometers. The step (b) includes irradiating the polarizer with the electromagnetic wave having a frequency of not less than 0.1 THz and not more than 0.8 THz to output an output wave having only a component parallel to a c-axis direction of the sapphire single crystalline layer.

## Claims

### Claim 1

A method for polarizing an electromagnetic wave having a frequency of not less than 0.1 THz and not more than 0.8 THz using a polarizer, the method comprising:
a step (a) of preparing the polarizer, wherein
the polarizer comprises:
a sapphire single crystalline layer; and
a CaxCoO2 crystalline layer, where x is not less than 0.15 and not more than 0.55, the CaxCoO2 crystalline layer is stacked on the sapphire single crystalline layer,
a surface of the CaxCoO2 crystalline layer has a (100) plane orientation, and
the CaxCoO2 crystalline layer has a thickness of not less than 2 micrometers and not more than 20 micrometers; and
a step (b) of irradiating the polarizer with the electromagnetic wave having a frequency of not less than 0.1 THz and not more than 0.8 THz to output an output wave having only a component parallel to a c-axis direction of the sapphire single crystalline layer.

### Claim 2 (depends on 1)

The method according to claim 1, wherein
the CaxCoO2 crystalline layer has a thickness of not less than 2 micrometers and not more than 9 micrometers.

### Claim 3 (depends on 1)

The method according to claim 1, wherein
the CaxCoO2 crystalline layer has a thickness of not less than 2 micrometers and not more than 4 micrometers.

### Claim 4 (depends on 1)

The method according to claim 1, wherein
in the step (b), the sapphire single crystalline layer is irradiated with the electromagnetic wave and the output wave is output from the CaxCoO2 crystalline layer.

### Claim 5 (depends on 1)

The method according to claim 1, wherein
in the step (b), the CaxCoO2 crystalline layer is irradiated with the electromagnetic wave and the output wave is output from the sapphire single crystalline layer.

### Claim 6 (depends on 1)

The method according to claim 1, wherein
in the step (b), the polarizer is irradiated with the electromagnetic wave travelling along a normal direction of the polarizer.

### Claim 7 (depends on 6)

The method according to claim 6, wherein
in the step (b), the output wave is output from the polarizer along the normal direction of the polarizer.

### Claim 8

A polarizer comprising:
a sapphire single crystalline layer; and
a CaxCoO2 crystalline layer, where x is not less than 0.15 and not more than 0.55, wherein:
the CaxCoO2 crystalline layer is stacked on the sapphire single crystalline layer,
a surface of the CaxCoO2 crystalline layer has a (100) plane orientation, and
the CaxCoO2 crystalline layer has a thickness of not less than 2 micrometers and not more than 20 micrometers.

### Claim 9 (depends on 8)

The polarizer according to claim 8, wherein
the CaxCoO2 crystalline layer has a thickness of not less than 2 micrometers and not more than 9 micrometers.

### Claim 10 (depends on 8)

The polarizer according to claim 8, wherein
the CaxCoO2 crystalline layer has a thickness of not less than 2 micrometers and not more than 4 micrometers.