U.S. Patent No. 8,201,268, issued on June 12, 2012 to OptoNet Inc. of Evanston, IL, discloses a sub-wavelength optical tip for a near-field scanning optical microscope (NSOM).

Due to the diffraction limit, resolution in conventional optical microscopy is limited so that features have to be larger than about one-half wavelength to be resolved.  In contrast, near-field scanning optical microscopy is able to image smaller features since its resolution is not diffraction-limited.  An NSOM scans a small optical tip (e.g., at the end of an optical waveguide) that serves as a light source in close proximity to the surface being imaged, and utilizes the evanescent field in the near-field region to detect the surface features.  The ’268 patent discloses an optical tip that has values of the refractive indices of the core and cladding of the waveguide which result in high energy throughput for near-field scanning operations and faster scanning speeds, with low localized heating at the probe.

According to its website, OptoNet “develops advanced, innovative photonic chips and modules based on proprietary approaches to monolithic integration of InP photonic devices” and “Si packaging platform design for avionic applications,” and its customers include the Navy and Air Force.  OptoNet has ties with Northwestern University’s Nano-Photonics and Quantum Electronics group.  For example, the inventors of the ’268 patent include Northwestern’s Professor S.T. Ho and Yingyan Huang, a former Ph.D. candidate, now President of OptoNet.

The company received a Small Business Innovative Research (SBIR) “Phase I” grant in 2008 of $100,000 from the National Science Foundation for developing an NSOM probe “utilizing an innovative high-refractive-index nanoscale waveguide (nanoWG) as the probing tip,” which sounds like the invention disclosed by the ’268 patent.  More recently, the company received a 2011 SBIR Phase I grant of $150,000 from the Department of Energy for developing a “proof-of-concept prototype,” with future work planned to develop ”a full series of ultra-high-power NSOM probe modules” that are plug-compatible with current NSOM probes.

According to the USPTO database, OptoNet owns four U.S. patents, three of which have been received in 2012.