White-light whispering gallery mode optical resonator system and method

• US 7,515,786 B1
• Filed: 07/21/2006
• Issued: 04/07/2009
• Est. Priority Date: 07/21/2006
• Status: Expired due to Fees

• Current Assignee: US Government As Represented By The Director National Security Agency
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Matsko, Andrey B., Maleki, Lute, Savchenkov, Anatoliy A.
• Primary Examiner(s): KIANNI, KAVEH C
• Application Number:
  US11/459,109
• Time in Patent Office: 991 Days
• Field of Search: 385/30, 385/13
• US Class Current: 385/30
• CPC Class Codes: G02B 6/29341 Loop resonators operating in a whispering gallery mode evanescently coupled to a light guide, e.g. sphere or disk or cylinder evanescent coupling for sensing fluorescence G01N21/648

Abstract

An optical resonator system and method that includes a whispering-gallery mode (WGM) optical resonator that is capable of resonating across a broad, continuous swath of frequencies is provided. The optical resonator of the system is shaped to support at least one whispering gallery mode and includes a top surface, a bottom surface, a side wall, and a first curved transition region extending between the side wall and the top surface. The system further includes a coupler having a coupling surface which is arranged to face the transition region of the optical resonator and in the vicinity thereof such that an evanescent field emitted from the coupler is capable of being coupled into the optical resonator through the first curved transition region.

Claims

1. An optical resonator system comprising:

an optical resonator, made substantially entirely from CaF₂, shaped to support at least one whispering gallery mode and comprising a top surface, a bottom surface, a side wall, and a first curved transition region extending between the side wall and the top surface; and

a coupler including a coupling surface, wherein the coupling surface defines a first plane and the optical resonator top surface defines a second plane wherein the first plane and second plane intersect at an acute angle;

wherein the coupling surface of the coupler is arranged to face the transition region of the optical resonator and in the vicinity thereof such that an evanescent field emitted from the coupler is capable of being coupled into the optical resonator through the first curved transition region.

2. The optical resonator system of claim 1, wherein the optical resonator is capable of resonating in a frequency range of an octave or more.

3. The optical resonator system of claim 1, wherein the coupler is a fiber coupler.

4. A device capable of (i) achieving power buildup at virtually any frequency inside an optical resonator, (ii) providing substantially constant Q factor at any frequency in the optical frequency, and (iii) providing substantially critical coupling of the optical resonator with a coupler, comprising:

an optical resonator shaped to support at least one whispering gallery mode and comprising a top surface, a bottom surface, a side wall, and a first curved transition region extending between the side wall and the top surface; and

a coupler including a coupling surface, wherein the coupling surface defines a first plane and the optical resonator top surface defines a second plane wherein the first plane and the second plane intersect at an acute angle;

wherein the coupling surface of the coupler is arranged to face the transition region of the optical resonator and in the vicinity thereof such that an evanescent field emitted from the coupler is capable of being coupled into the optical resonator through the first curved transition region.

5. An optical resonator system comprising:

an optical resonator shaped to support at least one whispering gallery mode and comprising a top surface, a bottom surface, a side wall, a first curved transition region extending between the side wall and the top surface, and a second curved transition region extending between the side wall and the bottom surface; and

a coupler including a coupling surface, wherein the coupling surface defines a first plane and the optical resonator top surface defines a second plane wherein the first plane and second plane intersect at an acute angle;

wherein the coupling surface of the coupler is arranged to face the transition region of the optical resonator and in the vicinity thereof such that an evanescent field emitted from the coupler is capable of being coupled into the optical resonator through the first curved transition region.

6. The optical resonator system of claim 5, wherein the optical resonator is a disk-shaped optical resonator defined by a diameter and wherein the top surface and the bottom surface are substantially parallel to each other.

7. The optical resonator system of claim 6, wherein the disk-shaped optical resonator includes a thickness defined between the top surface and the bottom surface of from about 50 μ

m to about 1000 μ

m and a diameter of from about 1 mm to about 1 cm.

8. The optical resonator system of claim 7, wherein the disk-shaped optical resonator comprises a thickness of about 500 μ

m and a diameter of about 0.5 cm.

9. The optical resonator system in claim 5, wherein the optical resonator comprises LiNbO₃, LiTaO₃, Al₂O₃, SiO₂, CaF₂, or a combination thereof.