The fully nonlinear response of a many-level noninteracting tunneling system to a strong alternating field of high frequency ω is studied in terms of the Schwinger-Keldysh nonequilibrium Greenșs functions. The nonlinear time dependent tunneling current I(t) is calculated exactly and its resonance structure is elucidated. In particular, it is shown that under certain reasonable conditions on the physical parameters, the Fourier component (Formula presented) is sharply peaked at n=(ΔE/ℏω), where ΔE is the spacing between two levels. This frequency multiplication results from the highly nonlinear process of n photon absorption (or emission) by the tunneling system. It is also conjectured that this effect (which so far is studied mainly in the context of nonlinear optics) might be experimentally feasible.
|Number of pages||12|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - 1 Jan 1997|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics