OPTICAL ELEMENT AND PHOTODETECTOR

• US 20130307108A1
• Filed: 05/07/2013
• Published: 11/21/2013
• Est. Priority Date: 05/16/2012
• Status: Active Grant

• Current Assignee: Hamamatsu Photonics KK
• Original Assignee: Hamamatsu Photonics KK
• Inventors: TANAKA, Kazunori, FUJITA, Kazuue, NAKAJIMA, Kazutoshi, HIROHATA, Toru, AKAHORI, Wataru
• Granted Patent: US 8,853,809 B2
• Time in Patent Office: Days
• US Class Current: 257/432
• CPC Class Codes: G02B 1/005 made of photonic crystals or photonic band gap materials photonic band-gap structures or photonic lattices in integrated optics G02B6/1225; photonic band-gap structures or photonic lattices in optical fibres G02B6/02295
• CPC Class Codes: H01L 31/02327 the optical elements being integrated or being directly associated to the device, e.g. back reflectors optical coatings H01L31/0216

Abstract

An optical element 10 for transmitting light therethrough along a predetermined direction and modulating the light comprises a structure 11 having a first region R1 and a second region R2 periodically arranged with respect to the first region R1 along a plane perpendicular to the predetermined direction, the first and second regions R1, R2 having respective refractive indexes different from each other, and properties of transmitting the light therethrough.

Claims

1. An optical element for transmitting light therethrough along a predetermined direction and modulating the light, the optical element comprising a structure having first regions and second regions periodically arranged with respect to the first regions along a plane perpendicular to the predetermined direction;

wherein the first and second regions have respective refractive indexes different from each other, and properties of transmitting the light therethrough.

2. An optical element according to claim 1, wherein the difference between the refractive indexes of the first and second regions is 2 or greater.

3. An optical element according to claim 1, wherein the first and second regions are arranged with a period of 1 to 500 μ

m.

4. An optical element according to claim 1, wherein the light is an infrared ray.

5. An optical element according to claim 1, wherein the structure has a film body provided with a plurality of through holes penetrating therethrough along the predetermined direction;

wherein the first region is a part between the through holes in the film body; and

wherein the second region is a space within the through hole.

6. An optical element according to claim 1, wherein the structure has a film body provided with a plurality of through holes penetrating therethrough along the predetermined direction and an embedded member held within the through hole;

wherein the first region is a part between the through holes in the film body; and

wherein the second region is the embedded member.

7. An optical element according to claim 1, wherein the structure has a film body provided with a plurality of depressions opening to one side or the other side in the predetermined direction;

wherein the first region is a part between the depressions in the film body; and

wherein the second region is a space within the depression.

8. An optical element according to claim 1, wherein the structure has a film body provided with a plurality of depressions opening to one side or the other side in the predetermined direction and an embedded member held within the through hole;

wherein the first region is a part between the depressions in the film body; and

wherein the second region is the embedded member.

9. An optical element according to claim 1, wherein the structure has a film body provided with a plurality of projections projecting to one side or the other side in the predetermined direction;

wherein the first region is the projection; and

wherein the second region is a space between the projections.

10. An optical element according to claim 1, wherein the structure has a film body provided with a plurality of projections projecting to one side or the other side in the predetermined direction and an embedded member held between the projections;

wherein the first region is the projection; and

wherein the second region is the embedded member.

11. A photodetector comprising:

the optical element according to claim 1;

a semiconductor multilayer body arranged on the other side opposite to one side in the predetermined direction with respect to the optical element and adapted to generate a current due to an electric field component in the predetermined direction in the light transmitted through the optical element;

a first contact layer formed on a surface on the one side of the semiconductor multilayer body; and

a second contact layer formed on a surface on the other side of the semiconductor multilayer body.

12. A photodetector according to claim 11, further comprising a substrate having the second contact layer, semiconductor multilayer body, first contact layer, and optical element sequentially stacked thereon from the other side.

13. A photodetector according to claim 11, further comprising:

a first electrode electrically connected to the first contact layer; and

a second electrode electrically connected to the second contact layer.

14. A photodetector according to claim 11, wherein the optical element generates the electric field component in the predetermined direction when light is incident thereon from the one side.

15. A photodetector according to claim 11, wherein the optical element generates the electric field component in the predetermined direction when light is incident thereon through the semiconductor multilayer body from the other side.