| Single-Mode WGM Resonators Fabricated by Diamond Turning |
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| NASA’s Jet Propulsion Laboratory | |
| Apr 30 2008 | |
Resonators having desired spectral responses can be reproduced efficiently.
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A diamond turning process has made possible a significant advance in the art of whispering-gallery- mode (WGM) optical resonators. By use of this process, it is possible to fashion crystalline materials into WGM resonators that have ultrahigh resonance quality factors (high Q values), are compact (ranging in size from millimeters down to tens of microns), and support single electromagnetic modes. This development combines and extends the developments reported in “Few-Mode Whispering-Gallery-Mode Resonators” (NPO-41256), NASA Tech Briefs, Vol. 30, No. 1 (January 2006), page 16a and “Fabrication of Submillimeter Axisymmetric Optical Components” (NPO-42056), NASA Tech Briefs, Vol. 31, No. 5 (May 2007), page 10a. To recapitulate from the first cited prior article: A WGM resonator of this special type consists of a rod, made of a suitable transparent material, from which protrudes a thin circumferential belt of the same material. The belt is integral with the rest of the rod and acts as a circumferential waveguide. If the depth and width of the belt are made appropriately small, then the belt acts as though it were the core of a single-mode optical fiber: the belt and the rod material adjacent to it support a single, circumferentially propagating mode or family of modes.  Circumferential Belts were formed by diamond turning on the initially cylindrical surface of a CaF2 rod. The radial depths and axial widths of the belts were chosen to make some of the belts act as single-mode and some as multi-mode WGM resonators. By virtue of its largely automated, computer-controlled nature, the process is suitable for mass production of nominally identical single-mode WGM resonators. In a demonstration of the capabilities afforded by this development, a number of WGM resonators of various designs were fabricated side by side on the surface of a single CaF2 rod (see figure). This work was done by Ivan Grudinin, Lute Maleki, Anatoliy Savchenkov, Andrey Matsko, Dmitry Strekalov, and Vladimir Iltchenko of Caltech for NASA’s Jet Propulsion Laboratory. In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to: Innovative Technology Assets Management Refer to NPO-43070, volume and number of this NASA Tech Briefs issue, and the page number. This Brief includes a Technical Support Package (TSP).
Single-Mode WGM Resonators Fabricated by Diamond Turning (reference NPO-43070) is currently available for download from the TSP library. Login first to download.
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