# US 12,184,036 B2 · Two-dimensional photonic-crystal surface-emitting laser

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- Number: US 12,184,036 B2
- Document ID: US12184036B2
- Status: Granted
- Kind: B2
- Application number: 17/632,896
- Filed: 2020-08-04
- Published: 2022-08-25
- Granted: 2024-12-31
- Earliest claimed: 2019-08-30
- Assignees: Kyoto University
- Applicants: Kyoto University
- Inventors: Susumu Noda; Takuya Inoue; Masahiro Yoshida; Menaka De Zoysa
- Web page: https://patentgrep.com/patent/US12184036B2

## CPC

- H01S 5/11: Comprising a photonic bandgap structure
- H01S 5/04256: {characterised by the configuration}
- H01S 5/18: Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities
- H01S 5/187: using Bragg reflection
- H01S 5/04254: {characterised by the shape}
- 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

## Abstract

A two-dimensional photonic-crystal surface-emitting laser includes an active layer, a two-dimensional photonic crystal, and electrodes. The two-dimensional photonic crystal contains a plate-shaped base material arranged on one side of the active layer and different refractive index portions arranged at lattice points of a predetermined lattice in the base material and having a refractive index different from that of the base material, a band edge frequency for each position in an electric current supply region, which is at least a part of the two-dimensional photonic crystal, is monotonically increased in one direction parallel to the base material. Such a two-dimensional photonic crystal occurs when the different refractive index portion has a refractive index smaller than that of the base material, a filling factor, which is a ratio of a volume occupied by the different refractive index portion in a unit lattice constituting the lattice, is monotonically increased in the one direction.

## Claims

### Claim 1

A two-dimensional photonic-crystal surface-emitting laser,
wherein the two-dimensional photonic-crystal surface-emitting laser is configured to emit a pulsed laser beam,
the two-dimensional photonic-crystal surface-emitting laser comprising:
a) an active layer;
b) a two-dimensional photonic crystal containing a base material having a plate shape and arranged on one side of the active layer and different refractive index portions arranged at lattice points of a predetermined lattice in the base material and having a refractive index different from that of the base material, a band edge frequency for each position in an electric current supply region, which is at least a part of the two-dimensional photonic crystal, is monotonically increased in one direction parallel to the base material; and
c) an electrode configured to continuously supply an electric current into the active layer and the electric current supply region.

### Claim 2 (depends on 1)

The two-dimensional photonic-crystal surface-emitting laser according to claim 1, wherein
the different refractive index portions have a refractive index smaller than that of the base material, and
a filling factor, which is a ratio of a volume occupied by a different refractive index portion in a unit lattice constituting the lattice, is monotonically increased in the electric current supply region in the one direction.

### Claim 3 (depends on 2)

The two-dimensional photonic-crystal surface-emitting laser according to claim 2, wherein a planar area of each of the different refractive index portions is monotonically increased in the one direction in the electric current supply region.

### Claim 4 (depends on 1)

The two-dimensional photonic-crystal surface-emitting laser according to claim 1, wherein
the different refractive index portions have a refractive index larger than that of the base material, and
a filling factor, which is a ratio of a volume occupied by a different refractive index portion in a unit lattice constituting the lattice, is monotonically decreased in the electric current supply region in the one direction.

### Claim 5 (depends on 4)

The two-dimensional photonic-crystal surface-emitting laser according to claim 4, wherein a planar area of each of the different refractive index portions is monotonically decreased in the one direction in the electric current supply region.

### Claim 6 (depends on 1)

The two-dimensional photonic-crystal surface-emitting laser according to claim 1, wherein a period length of the lattice is monotonically decreased in the one direction in the electric current supply region.

### Claim 7 (depends on 1)

The two-dimensional photonic-crystal surface-emitting laser according to claim 1, wherein the band edge frequency is continuously increased in the one direction in the electric current supply region.

### Claim 8 (depends on 1)

The two-dimensional photonic-crystal surface-emitting laser according to claim 1, wherein the band edge frequency is increased stepwise in the one direction in the electric current supply region.

### Claim 9 (depends on 1)

The two-dimensional photonic-crystal surface-emitting laser according to claim 1, wherein each of the different refractive index portions has a non-circular planar shape.