Potential and limits of superlattice multipliers coupled to different input power sources

Abstract

A theoretical study is presented to assess the performance of semiconductor superlattice multipliers as a function of the currently available input power sources. The prime devices which are considered as input power sources are Impatt diodes, InP Gunn devices, superlattice electron devices and Backward Wave Oscillator sources. These sources have been successfully designed to deliver input radiation frequencies in the range from 0.1 to 0.5 THz. We discuss the harmonic power generation of both odd and even harmonics by implementing an ansatz solution stemmed from a hybrid approach combining nonequilibrium Green's functions and the Boltzmann kinetic equation.

Giant controllable gigahertz to terahertz nonlinearities in superlattices

“…The experiments in Fig. 3 clearly demonstrate that the nonlinearities can be controlled and enhanced as predicted by the theory, but note that the structural defects, imperfect interfaces 7 , 8 , 19 , 20 and possible charge field domains make the experimental I–V different to the ideal I–V used in the theory, see Fig. 2 c, so it is normal that the nonlinear response would have some quantitative deviations from the ideal solution.…”

“…The experiments have been performed with GHz input leading to THz output, demonstrating full control and enhancement of the nonlinearities in terms of applied voltage and power, in a regime that can be studied with input fields from compact devices 19,20 . A clear-cut proof of the role of asymmetric flow in our own data is highlighted in Fig.…”

“…Furthermore, the experiments were realized at 10 K, while ours is a direct control room, temperature demonstration. Note also that the very interesting studies of control of THz high-harmonic generation by dynamical Bloch oscillations require super intense THz pulses and control was actually at pulse generation level requiring large energy fs-source 20 . Nonlinear crystals have delivered pulsed, tunable GHz to THz sources, but also relied upon large pulsed sources 21 – 24 .…”

Combined Structural and Voltage Control of Giant Nonlinearities in Semiconductor Superlattices

“…where the speed of light is c 2 = 1/µ 0 0 . Simplifying the Boltzmann equation for carrier transport with relaxation approximation, one can show that if the superlattice is illuminated with combined static and monochromatic fields [1,28,[38][39][40][41][42],…”

“…Strong excitonic effects can also play a role under well-defined conditions [35][36][37]. All these processed can be somehow be combined to enhance HHG in SSLMs; however, in this paper we focus on the combined effect of a uniform bias and Nanomaterials 2021, 11, 1287 2 of 8 current-voltage asymmetry on the Bloch oscillations modulation, which has successfully predicted giant voltage control of HHG in unbiased SSLMs [28,[38][39][40][41][42].…”