Photoconductive antenna, terahertz wave generating device, camera, imaging device, and measuring device

Patent metadata

Field	Value
Publication number	US-9349917-B2
Application number	US-201514818585-A
Country	US
Kind code	B2
Filing date	Aug 5, 2015
Priority date	Jan 18, 2012
Publication date	May 24, 2016
Grant date	May 24, 2016

Abstract

A photoconductive antenna is adapted to generate terahertz waves when irradiated by pulsed light. The photoconductive antenna includes a semiconductor layer, a first conductive layer, a second conductive layer, a first electrode and a second electrode. The first conductive layer is disposed on a first surface of the semiconductor layer. The second conductive layer is disposed on the first surface of the semiconductor layer with a prescribed gap being formed between the first conductive layer and the second conductive layer. The first electrode is electrically connected to the first conductive layer. The second electrode is electrically connected to the second conductive layer. The first conductive layer contains a first conductive type impurity. The second conductive layer contains a second conductive type impurity. The semiconductor layer has a carrier density lower than a carrier density of the first conductive layer or a carrier density of the second conductive layer.

First claim

What is claimed is:

1. A photoconductive antenna adapted to generate terahertz waves when irradiated by pulsed light, the photoconductive antenna comprising:
a semiconductor layer;
a first conductive layer disposed on a first surface of the semiconductor layer;
a second conductive layer disposed on the first surface of the semiconductor layer with a prescribed gap being formed between the first conductive layer and the second conductive layer;
a first electrode electrically connected to the first conductive layer; and
a second electrode electrically connected to the second conductive layer, wherein
the first conductive layer contains a first conductive type impurity,
the second conductive layer contains a second conductive type impurity, and
the semiconductor layer has a carrier density lower than a carrier density of the first conductive layer or a carrier density of the second conductive layer.

2. The photoconductive antenna according to claim 1 , wherein
the first electrode has the same shape as the first conductive layer in a top plan view, and
the second electrode has the same shape as the second conductive region in the top plan view.

3. A terahertz wave generating device comprising:
the photoconductive antenna according to claim 2 ; and
a light source configured and arranged to generate the pulsed light.

4. A camera comprising:
the photoconductive antenna according to claim 2 ;
a light source configured and arranged to generate the pulsed light; and
a terahertz wave detecting unit configured and arranged to detect terahertz waves emitted from the photoconductive antenna and reflected by an object.

5. The photoconductive antenna according to claim 1 , further comprising
an insulation layer disposed on the semiconductor layer in at least a portion within the prescribed gap between the first conductive layer and the second conductive layer in a top plan view.

6. A terahertz wave generating device comprising:
the photoconductive antenna according to claim 5 ; and
a light source configured and arranged to generate the pulsed light.

7. A camera comprising:
the photoconductive antenna according to claim 5 ;
a light source configured and arranged to generate the pulsed light; and
a terahertz wave detecting unit configured and arranged to detect terahertz waves emitted from the photoconductive antenna and reflected by an object.

8. An imaging device comprising:
the photoconductive antenna according to claim 5 ;
a light source configured and arranged to generate the pulsed light;
a terahertz wave detecting unit configured and arranged to detect terahertz waves emitted from the photoconductive antenna and transmitted through an object or reflected by the object; and
an image forming unit configured and arranged to generate an image of the object based on detection results of the terahertz wave detecting unit.

9. The imaging device according to claim 8 , wherein
the image forming unit is configured and arranged to generate the image of the object using intensity of the terahertz waves detected by the terahertz wave detecting unit.

10. A measuring device comprising:
the photoconductive antenna according to claim 5 ;
a light source configured and arranged to generate the pulsed light;
a terahertz wave detecting unit configured and arranged to detect terahertz waves emitted from the photoconductive antenna and transmitted through an object or reflected by the object; and
a measuring unit configured and arranged to measure the object based on detection results of the terahertz wave detecting unit.

11. The measuring device according to claim 10 , wherein
the measuring unit is configured and arranged to measure the object using intensity of the terahertz waves detected by the terahertz wave detecting unit.

12. The photoconductive antenna according to claim 1 , wherein
the semiconductor material of the semiconductor layer is a III-V compound.

13. A terahertz wave generating device comprising:
the photoconductive antenna according to claim 12 ; and
a light source configured and arranged to generate the pulsed light.

14. A camera comprising:
the photoconductive antenna according to claim 12 ;
a light source configured and arranged to generate the pulsed light; and
a terahertz wave detecting unit configured and arranged to detect terahertz waves emitted from the photoconductive antenna and reflected by an object.

15. A terahertz wave generating device comprising:
the photoconductive antenna according to claim 1 ; and
a light source configured and arranged to generate the pulsed light.

16. A camera comprising:
the photoconductive antenna according to claim 1 ;
a light source configured and arranged to generate the pulsed light; and
a terahertz wave detecting unit configured and arranged to detect terahertz waves emitted from the photoconductive antenna and reflected by an object.

17. An imaging device comprising:
the photoconductive antenna according to claim 1 ;
a light source configured and arranged to generate the pulsed light;
a terahertz wave detecting unit configured and arranged to detect terahertz waves emitted from the photoconductive antenna and transmitted through an object or reflected by the object; and
an image forming unit configured and arranged to generate an image of the object based on detection results of the terahertz wave detecting unit.

18. The imaging device according to claim 17 , wherein
the image forming unit is configured and arranged to generate the image of the object using intensity of the terahertz waves detected by the terahertz wave detecting unit.

19. A measuring device comprising:
the photoconductive antenna according to claim 1 ;
a light source configured and arranged to generate the pulsed light;
a terahertz wave detecting unit configured and arranged to detect terahertz waves emitted from the photoconductive antenna and transmitted through an object or reflected by the object; and
a measuring unit configured and arranged to measure the object based on detection results of the terahertz wave detecting unit.

20. The measuring device according to claim 19 , wherein
the measuring unit is configured and arranged to measure the object using intensity of the terahertz waves detected by the terahertz wave detecting unit.

Assignees

• Seiko Epson Corp

Inventors

• Takenaka Satoshi

Classifications

• G01J5/10

  using electric radiation detectors · CPC title

• G01N21/3586

  by Terahertz time domain spectroscopy [THz-TDS] · CPC title

• G02F2203/13

  involving THZ radiation · CPC title

• G02F2202/12

  photoconductor · CPC title

• G01J2005/0077

  Imaging · CPC title