Periodically pulsed laser-assisted tunneling may generate terahertz radiation
- NewPath Research L.L.C., Salt Lake City, UT (United States)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
In this work, a mode-locked ultrafast laser focused on the tunneling junction of a scanning tunneling microscope superimposes harmonics of the laser pulse repetition frequency on the direct current tunneling current. The power measured at the first 200 harmonics (up to 14.85 GHz) varies as the inverse square of the frequency due to shunting by the stray capacitance and the resistance in the circuit. However, Fourier analysis suggests that within the tunneling junction there is no significant decay of the harmonics until terahertz frequencies comparable to the reciprocal of the laser pulse-width. Two different types of analysis are used to model the generation of the frequency comb within the tunneling junction. Similar results are obtained, suggesting that the harmonics may extend to terahertz frequencies. Thus, the tunneling junction may be used as a subnanometer sized source of terahertz radiation.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- 89233218CNA000001; AC52-06NA25396
- OSTI ID:
- 1505991
- Alternate ID(s):
- OSTI ID: 1680015
- Report Number(s):
- LA-UR-17-20587; LA-UR-16-28593
- Journal Information:
- Journal of Vacuum Science and Technology B, Vol. 35, Issue 3; ISSN 2166-2746
- Publisher:
- American Vacuum Society/AIPCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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