Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras
Method and Optical Device for Excitation of Whispering Gallery Mode (WGM) in Micro-cavity Structure
Technology Category/Market
Technology: Optical device for excitation of whispering gallery mode in a microcavity structure; Industry: Medical Industries, Environmental Monitoring, Defense, etc.;
Applications: Sensing Applications, Biomedical sensing, Fiber Optic Chemical Sensing, etc.
Market: The global optical chemical sensors market size is projected at a CAGR of 16.1% during period of 2023-2030.
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Problem Statement
- In the instant, a probing level of aquatic contaminants is proposed with a fast & reliable opto-chemical sensor platform based on a surface-functionalized optical micro-resonator device (microbottle resonator) coupled naturally to an optical fiber.
- Whispering gallery modes (WGM) in microbottle resonators, is providing strong confinement of light carriers in very smallscale resonators.
- Further, a few prior arts have discussed related to excitation using a carefully aligned waveguide at the neck region of the micro bottle resonator, however unable to provide solutions in the scenario of excitation of the WGM through the stem of the microbottle resonator.
- Hence, there is a need to mitigate above challenges, which is addressed efficiently in the present invention.
Technology
- Present invention describes a method for excitation of Whispering Gallery Mode (WGM) in a microcavity structure by an optical device.
- An optical beam with the OAM comprises a transverse field pattern overlapping a transverse field pattern of the at least one WGM,
- The transverse field pattern of the optical beam with the OAM and the transverse field pattern of the at least one WGM is helical shown in figures.
- The optical device couples the optical beam with one of the OAM possessing charge (l~10-500) vortices comprising large off-axis Poynting vectors compatible with the excitation of the at least one WGM in the micro-cavity structure.
- The method & optical device for excitation of whispering gallery mode in a micro-cavity structure by passing an optical beam with orbital angular momentum from an end of an optical cable shown in fig.2 & flowchart
Key Features/Value Proposition
Technical Perspective:
- Present invention is focused on optimizing the coupling efficiency between the OAM mode & the WGM in micro bottle resonator as well as demonstrating the WGM excitation experimentally.
- The coupling facility is done by using an active dopant in the micro-cavity structure.
- Bottle microresonators can be excited (and the signal may be extracted) through the fiber stems associated with the bottle micro-resonator, making the excitation mechanism relatively simple & robust.
- Field pattern of the WGM is very similar to that of the optical beam with the OAM, hence the WGM in the structure, for example a micro bottle resonator fiber is excited using the OAM beam.
- Facilitates the optical frequency range i.e.100s of THz.
User Perspective:
- Provides a cost-effective, simple, & eco-friendly method.
Questions about this Technology?
Contact for Licensing
Research Lab
Prof. Balaji Srinivasan,
Department of Electrical Engineering
Prof. Prem B Bisht
Department of Physics
Intellectual Property
IITM IDF Ref.:2203
Patent No. 446634
Technology Readiness Level
TRL- 3/4
Proof of Concept, Tested & validated