SBIR Phase I: Ultrafast Optoelectronic Devices Based on Field Emission

This Small Business Innovation Research Phase I project proposes to determine the feasibility of using photomixing (optical heterodyning) in resonant laser-assisted field emission as a new means for generating terahertz (THz) radiation. The many applications of THz radiation include imaging (package inspection, structural examination, cancer detection), spectroscopy (catalysis, reaction kinetics, environmental studies), astronomy (local oscillators, imaging arrays), and high-bandwidth communications. However, researchers describe "hurdles" caused by present THz sources, including limited bandwidth and power. A resonance of optical radiation with tunneling electrons, discovered in quantum simulations, was used to gate field emission current with a laser. Because the tip is much smaller than the laser wavelength, electron emission varies at the optical frequency, and field emission is highly nonlinear, so signals from DC to 100 THz could be generated by photomixing. The commercial applications of this project would be tunable sources with greater bandwidth. These devices are now used as local oscillators in radio astronomy.There is some evidence that the new technology may have a flat frequency response at THz frequencies. Possible applications of resonant laser-assisted field emission would also include areas where the resistance of field emission to ionizing radiation and wide ranges of ambient temperature are required.