STTR Phase II: Surface Plasmon Enhanced High Efficiency Near-field Probes

This Small Business Technology Transfer (STTR) Phase II project will further develop structures and manufacturing techniques for high efficiency near-field scanning optical microscope (NSOM) probes utilizing surface plasmon enhancement. Wavelength scale surface topography (gratings) in metal films allow coupling between surface plasmons at the metal interface and photons in free space, providing significant transmission enhancement through sub-wavelength apertures. Probes with 20 nanometers optical and topographic resolution combined with power throughput greater than 10 microwatts are projected. This represents a factor of 5-10 improvement in resolution and a thousand fold improvement in transmission over existing tapered fiber NSOM probes. The program will include closely linked fabrication, theoretical modeling, and characterization activities to ensure efficient optimization. The plasmon structures will be integrated with optical fibers to produce NSOM probes that can be directly interchanged with existing tapered fiber probes. In addition to the primary development of improved NSOM probes, advancements to the fundamental scientific understanding of plasmon-optical interactions will aid in the future development of other plasmonic devices. Commercially the proposed program will enhance the capabilities of NSOM metrology instruments, which have wide applicability in nanotechnology development. Based on Phase I results, significant increases in measurement speed and improved resolution can be expected from this effort. The proposed effort is a key step in commercialization of a large area, high speed NSOM instrument. While this project focuses specifically on NSOM tips, plasmon optics have potential applications to a broad range of areas where high efficiency and subwavelength sizes are required including the integration of optics with microelectronics, spatial and spectral optical multiplexing, and data storage applications.