Narrow Results

We investigate the response of electrons confined in a quantum wire in the presence of intense terahertz (THz) electric field. An exact and powerful nonperturbative fundamental approach of Floquet theory is employed to solve the equation of motion for resonantly driven intersubband transitions. Several interesting features namely dynamic Stark shift, power broadening and hole-burning are observed with the variation in electric field strength. In addition, the degeneracy between several excited states is found to be removed in the presence of high electric field.

The nonlinear interaction of electromagnetic radiation in microwave, terahertz, and optical regions with non-uniformly distributed space charge in the interelectrode space of vacuum devices is investigated. The detection of electromagnetic radiation in the vacuum electronic tubes (diode and triode) with parallel plate electrodes is experimentally demonstrated. The dependence of the detected signal on the incident radiation power, direction of wave polarization, current characteristics and frequency of modulating signal has been investigated.

The equation of motion of an electron in the field of electromagnetic wave in the presence of space charge was obtained, according to which, the detection is due to nonlinearity associated with the non-uniform distribution of electrons along the electrostatic field direction.

The measured detection characteristics are in reasonable agreement with theoretical estimates.