Surface emitting laser element, surface emitting laser, surface emitting laser device, light source device, and detection apparatus

Patent metadata

Field	Value
Publication number	US-11901701-B2
Application number	US-202017088599-A
Country	US
Kind code	B2
Filing date	Nov 4, 2020
Priority date	Nov 22, 2019
Publication date	Feb 13, 2024
Grant date	Feb 13, 2024

Abstract

A surface emitting laser element includes a first reflecting mirror; an active layer over the first reflecting mirror; a second reflecting mirror over the active layer; and a multilayer film over the second reflecting mirror. The multilayer film has a side surface including one film and inclined with respect to a principal surface of the second reflecting mirror. The multilayer film includes, in a thickness direction, two or more pairs of a first film having a first refractive index and a second film having a second refractive index higher than the first refractive index. The multilayer film has a center portion and a peripheral portion around the center portion in plan view in a direction perpendicular to the principal surface. The peripheral portion includes the side surface.

First claim

The invention claimed is:

1. A surface emitting laser element, comprising:
a first reflecting mirror;
an active layer over the first reflecting mirror;
a second reflecting mirror over the active layer;
a multilayer film over the second reflecting mirror, the multilayer film having a center portion and a peripheral portion around the center portion in plan view in a direction perpendicular to a principal surface of the second reflecting mirror;
a first portion where the center portion overlaps the second reflecting mirror in the plan view; and
a second portion where the peripheral portion overlaps the second reflecting mirror in the plan view, wherein
the multilayer film has a side surface including one film inclined with respect to the principal surface of the second reflecting mirror, the peripheral portion including the side surface,
the multilayer film includes, in a thickness direction, two or more pairs of a first film having a first refractive index and a second film having a second refractive index higher than the first refractive index, and
a first reflectivity of the first portion is greater than a second reflectivity of the second portion.

2. The surface emitting laser element according to claim 1 , wherein the one film is the second film included in an uppermost one of the two or more pairs.

3. The surface emitting laser element according to claim 1 , wherein the multilayer film has two or more pairs of the first film and the second film entirely in the center portion and the peripheral portion.

4. The surface emitting laser element according to claim 3 , wherein a ratio of a thickness of the first film to a thickness of the second film in the center portion is equal to a ratio of a thickness of the first film to a thickness of the second film in the peripheral portion.

5. The surface emitting laser element according to claim 1 , wherein the one film includes a third film having a same composition as a composition of the second film.

6. The surface emitting laser element according to claim 1 , wherein
the first reflecting mirror and the second reflecting mirror each include a semiconductor-multilayer-film reflecting mirror, and
the first film and the second film each include a dielectric film.

7. The surface emitting laser element according to claim 1 , wherein light is emitted from a side of the first reflecting mirror.

8. A surface emitting laser, comprising:
a substrate; and
a plurality of surface emitting laser elements each according to claim 1 , wherein
the plurality of surface emitting laser elements are on the substrate, and
for each surface emitting laser element, the first reflecting mirror is nearer the substrate than the second reflecting mirror.

9. A surface emitting laser device, comprising:
a mount substrate; and
the surface emitting laser according to claim 8 mounted on the mount substrate.

10. A light source device, comprising:
the surface emitting laser device according to claim 9 ; and
a driver configured to drive the surface emitting laser device.

11. A detection apparatus, comprising:
the light source device according to claim 10 ; and
a photosensor configured to detect light emitted outside from the surface emitting laser and reflected by an object.

12. The surface emitting laser element according to claim 1 , wherein the second reflectivity monotonously decreases with an increase in a distance from the center portion in a direction orthogonal to the thickness direction.

13. The surface emitting laser element according to claim 1 , further comprising:
a confinement structure disposed in an electrical path to the active layer, the confinement structure including a current passing region through which a current passes, wherein
the center portion of the multilayer film is above the current passing region.

14. A surface emitting laser element comprising:
a first reflecting mirror;
an active layer over the first reflecting mirror;
a second reflecting mirror over the active layer;
a multilayer film over the second reflecting mirror, the multilayer film having a center portion and a peripheral portion around the center portion in plan view in a direction perpendicular to a principal surface of the second reflecting mirror;
a first portion where the center portion overlaps the second reflecting mirror in the plan view; and
a second portion where the peripheral portion overlaps the second reflecting mirror in the plan view, wherein
the multilayer film has a side surface inclined with respect to the principal surface of the second reflecting mirror and covered with one film, the peripheral portion including the side surface,
the multilayer film includes, in a thickness direction, two or more pairs of a first film having a first refractive index and a second film having a second refractive index higher than the first refractive index, and
the peripheral portion has a reflectivity lower than a reflectivity of the center portion.

15. The surface emitting laser element according to claim 14 , wherein
the first reflecting minor and the second reflecting mirror each include a semiconductor-multilayer-film reflecting mirror, and
the first film and the second film each include a dielectric film.

16. The surface emitting laser element according to claim 14 , wherein light is emitted from a side of the first reflecting mirror.

17. A surface emitting laser, comprising:
a substrate; and
a plurality of surface emitting laser elements each according to claim 14 , wherein
the plurality of surface emitting laser elements are on the substrate, and
for each surface emitting laser element, the first reflecting mirror is nearer the substrate than the second reflecting mirror.

18. A surface emitting laser device, comprising:
a mount substrate; and
the surface emitting laser according to claim 17 mounted on the mount substrate.

19. A light source device, comprising:
the surface emitting laser device according to claim 18 ; and
a driver configured to drive the surface emitting laser device.

20. A detection apparatus, comprising:
the light source device according to claim 19 ; and
a photosensor configured to detect light emitted outside from the surface emitting laser and reflected by an object.

Assignees

• Hanaoka Katsunari
• Fujiwara Masayuki
• Ricoh Co Ltd

Inventors

• Hanaoka Katsunari
• Fujiwara Masayuki

Classifications

• H01S5/18369 Primary

  based on dielectric materials · CPC title

• H01S5/023

  Mount members, e.g. sub-mount members · CPC title

• H01S5/0206

  Substrates, e.g. growth, shape, material, removal or bonding; (specific crystal orientation H01S5/3202) · CPC title

• H01S5/0233

  Mounting configuration of laser chips · CPC title

• H01S5/0235

  Method for mounting laser chips · CPC title