Antenna feedback scheme for achieving narrow beam emission from plasmonic lasers

Patent metadata

Field	Value
Publication number	US-9660416-B2
Application number	US-201514984652-A
Country	US
Kind code	B2
Filing date	Dec 30, 2015
Priority date	Dec 30, 2014
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

A distributed antenna-coupling feedback scheme and specially designed distributed feedback (DFB) metallic cavity and grating for laser application and in particular to plasmonic lasers ensuring a predesigned phase condition such that a mode traveling inside a waveguide is coupled/phase-locked to a mode traveling on the top metal improving the beam quality of the laser.

First claim

What is claimed is:

1. A plasmonic laser comprising:
an optical cavity enclosed in a surrounding medium;
a metallic cladding surrounding the optical cavity;
an optical gain medium enclosed in the cavity; and
a periodic structure implemented in at least one of the cladding and the optical cavity, wherein the periodic structure is determined from a phase match condition, such that upon pumping of the gain medium a coupling is established between a first guided electromagnetic wave in the optical cavity and a second guided electromagnetic wave in the surrounding medium.

2. The plasmonic laser according to claim 1 , wherein the first and second guided waves are surface-plasmon-polaritons (“SPPs”).

3. The plasmonic laser according to claim 1 , wherein the coupling between the first and second guided waves establishes a phase lock between the waves.

4. The plasmonic laser according to claim 3 , wherein the periodic structure comprises a grating in the cavity, which facilitates the coupling.

5. The plasmonic laser according to claim 4 , wherein the grating diffracts the first guided wave due to generate the second guided wave.

6. The plasmonic laser according to claim 5 , wherein the grating has a period determined by the phase match condition between the first guided wave and the second guided wave.

7. The plasmonic laser according to claim 1 , wherein the phase match condition is

k
i

=

p
⁢

2
⁢
π

Λ

+

k
d

wherein K 1 is a wave number of an incident wave, k d is a wave number of a diffracted wave, p is an integer specifying a diffraction order (p=+/−1, +/−2, +/−3 . . . ) and Λ is the period of the grating.

8. The plasmonic laser according to claim 1 , wherein the cavity is a Fabry-Pérot cavity.

9. The plasmonic laser according to claim 1 , wherein the second guided wave is generated by Bragg diffraction.

10. The plasmonic laser according to claim 1 , wherein the second guided wave further comprises a propagating quasi-cylindrical wave.

11. A method for generating a narrow beam in a plasmonic laser comprising:
introducing a periodic structure determined from a phase match condition in a boundary separating an optical cavity and a surrounding medium; and
pumping the optical cavity, wherein a phase coupling is established between a first guided electromagnetic wave generated in the optical cavity and a second guided electromagnetic wave generated in the surrounding medium.

12. The method according to claim 11 , wherein the first and second guided waves are surface-plasmon-polaritons (“SPPs”).

13. The method according to claim 11 , wherein the periodic structure comprises a grating further comprising a plurality of apertures.

14. The method according to claim 13 , wherein the grating diffracts a first guided wave due to the periodic perturbation to generate the second guided wave.

15. The method according to claim 11 , wherein the phase match condition is

k
i

=

p
⁢

2
⁢
π

Λ

+

k
d

⁢

⁢

k
i

=

p
⁢

2
⁢
π

Λ

+

k
d

wherein k i is a wave number of an incident wave, k d is a wave number of a diffracted wave, p is an integer specifying a diffraction order (p=+/−1, +/−2, +/−3 . . . ) and Λ is a period of the grating.

Assignees

• Univ Lehigh

Inventors

• Kumar Sushil
• Wu Chongzhao

Classifications

• H01S5/1046

  Comprising interactions between photons and plasmons, e.g. by a corrugated surface · CPC title

• H01S5/3402

  intersubband lasers, e.g. transitions within the conduction or valence bands · CPC title

• H01S2302/02

  THz - lasers, i.e. lasers with emission in the wavelength range of typically 0.1 mm to 1 mm · CPC title

• H01S5/12 Primary

  the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers (comprising a photonic bandgap structure H01S5/11; surface-emitting lasers H01S5/18) · CPC title