Infrared laser

• US 9,065,246 B2
• Filed: 09/09/2014
• Issued: 06/23/2015
• Est. Priority Date: 11/14/2011
• Status: Active Grant

• Current Assignee: The Government Of The United States Of America, As Represented By The Secretary Of The Navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Kub, Francis J., Currie, Marc
• Primary Examiner(s): NGUYEN, TUAN N
• Application Number:
  US14/480,757
• Publication Number:
  US 20140376585A1
• Time in Patent Office: 287 Days
• Field of Search: 372/70
• US Class Current: 1/1
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01S 3/06 Construction or shape of active medium
• CPC Class Codes: H01S 3/081 comprising three or more reflectors
• CPC Class Codes: H01S 3/0813 Configuration of resonator
• CPC Class Codes: H01S 3/0815 having 3 reflectors, e.g. V-shaped resonators
• CPC Class Codes: H01S 3/083 Ring lasers fibre ring lasers H01S3/06791
• CPC Class Codes: H01S 3/0906 Electrical, electrochemical, or electron-beam pumping of a dye laser
• CPC Class Codes: H01S 3/091 using optical pumping
• CPC Class Codes: H01S 3/10 Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
• CPC Class Codes: H01S 3/1106 Mode locking
• CPC Class Codes: H01S 3/1112 Passive mode locking
• CPC Class Codes: H01S 3/1115 using intracavity saturable absorbers
• CPC Class Codes: H01S 3/1118 Semiconductor saturable absorbers, e.g. semiconductor saturable absorber mirrors [SESAMs]; Solid-state saturable absorbers, e.g. carbon nanotube [CNT] based
• CPC Class Codes: H01S 3/113 using intracavity saturable absorbers
• CPC Class Codes: H01S 5/028 Coatings ; Treatment of the laser facets, e.g. etching, passivation layers or reflecting layers
• CPC Class Codes: H01S 5/0601 comprising an absorbing region H01S5/0604, H01S5/0607, H01S5/0615 and H01S5/065 take precedence; bistable laser devices in general G02F3/026
• CPC Class Codes: H01S 5/10 Construction or shape of the optical resonator , e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region H01S5/20 takes precedence
• CPC Class Codes: H01S 5/1032 Coupling to elements comprising an optical axis that is not aligned with the optical axis of the active region
• CPC Class Codes: H01S 5/14 External cavity lasers H01S5/18 takes precedence; mode locking H01S5/065
• CPC Class Codes: H01S 5/1838 Reflector bonded by wafer fusion or by an intermediate compound
• CPC Class Codes: H01S 5/3401 : having no PN junction, e.g. unipolar lasers, intersubband lasers, quantum cascade lasers
• CPC Class Codes: H01S 5/50 : Amplifier structures not provided for in groups H01S5/02 - H01S5/30

Abstract

Laser devices are presented in which a graphene saturable absorber and an optical amplifier are disposed in a resonant optical cavity with an optical or electrical pump providing energy to the optical amplifier.

Claims

1. A laser device, comprising:

a first mirror with a first surface;

a second mirror with a second surface at least partially facing the first surface of the first mirror, the first and second mirrors defining a resonant optical cavity in which electromagnetic energy is amplified by stimulated emission of coherent radiation that is partially transmitted through the second mirror;

a semiconductor optical amplifier disposed at least partially between the first and second surfaces;

wherein the semiconductor optical amplifier gain exceeds the loss for a time of about <

1 ms within the resonant optical cavity;

an electrical or optical pump providing energy to the semiconductor optical amplifier; and

a graphene saturable absorber disposed at least partially between the first and second surfaces;

wherein the graphene saturable absorber operates as a variable loss mechanism in the optical cavity allowing population inversion if the gain material exceeds the lasing threshold without the graphene and causing the stored optical energy to be released in optical pulses;

wherein the laser device emits pulses stimulated coherent radiation through the second mirror with center wavelengths of about 1,800 nm or more and about 25,000 nm or less.

2. The laser device of claim 1, wherein the semiconductor optical amplifier comprises a superlattice of alternating semiconductor layers of at least two different material compositions.

3. The laser device of claim 1, wherein the graphene saturable absorber is disposed between the first surface and the semiconductor optical amplifier.

4. The laser device of claim 1, wherein the laser device is a frequency comb laser.

5. A linear cavity laser device, comprising:

a first mirror with a first surface;

a second mirror with a second surface at least partially facing the first reflective surface of the first mirror, the first and second mirrors defining a resonant optical cavity in which electromagnetic energy is amplified by stimulated emission of coherent radiation that is partially transmitted through the second mirror;

a semiconductor optical amplifier disposed at least partially between the first and second surfaces;

wherein the semiconductor optical amplifier gain exceeds the loss within the resonant optical cavity over a broad spectral bandwidth;

an electrical or optical pump providing energy to the semiconductor optical amplifier; and

a graphene saturable absorber integral with the second mirror at least partially between the semiconductor optical amplifier and the second surface;

wherein the graphene saturable absorber operates in a passive mode;

wherein the laser device emits pulses stimulated coherent radiation through the second mirror with center wavelengths of about 1,800 nm or more and about 25,000 nm or less;

and wherein comprising a top electrode formed above a top surface of the semiconductor optical amplifier, the top electrode including a transparent graphene material layer.

6. The linear cavity laser device of claim 5, wherein the graphene saturable absorber is spaced from the semiconductor optical amplifier.

7. The linear cavity laser device of claim 5, wherein the semiconductor optical amplifier is a vertical cavity surface optical amplifier disposed at least partially between the first and second surfaces.

8. The linear cavity laser device of claim 5, wherein the top electrode comprises a spacer material layer between at least a portion of the top surface of the semiconductor optical amplifier and the transparent graphene material layer.

9. The linear cavity laser device of claim 5, wherein the top electrode comprises a metal material layer formed above at least a portion of the transparent graphene material layer.

10. The linear cavity laser device of claim 5, wherein the metal material layer includes an aperture exposing at least a portion of the transparent graphene material layer.

11. The linear cavity laser device of claim 5, wherein the top electrode comprises a metal material layer formed above at least a portion of the transparent graphene material layer.

12. The linear cavity laser device of claim 11, wherein the metal material layer includes an aperture exposing at least a portion of the transparent graphene material layer.

13. The linear cavity laser device of claim 5, wherein the semiconductor optical amplifier comprises opposite first and second ends with the first end facing the first mirror and the second end facing the second mirror, wherein the graphene saturable absorber is bonded to the second end of the semiconductor optical amplifier, and wherein the second mirror is integral with the graphene saturable absorber to provide a monolithic laser structure.

14. The linear cavity laser device of claim 5, wherein the laser device is a mode-locked laser or a Q-switched laser configured to emit stimulated coherent radiation through the second mirror with center wavelengths of about 1,800 nm or more and about 25,000 nm or less.

15. The linear cavity laser device of claim 5, wherein the laser device is a mode-locked laser or a Q-switched laser configured to emit stimulated coherent radiation through the second mirror with center wavelengths of about 280 nm or more and about 1,800 nm.

16. The linear cavity laser device of claim 5, wherein the laser device is a mode-locked laser or a Q-switched laser configured to emit stimulated coherent radiation through the second mirror and having a spectral width of about 10% of the center wavelength.