Bloch oscillations in superlattices

We have demonstrated the possibility of a Bloch oscillator emitting bias tunable submillimeter-wave radiation. The tuning range covers about one order of magnitude from 0.5 up to 5 THz, with the dependence on the applied electric field in excellent agreement with theory. For the first time this could be demonstrated even at the technologically important temperature of 77 K and up to 200 K. It is interesting to speculate whether BO can be observed at room temperature. T (ind 2) at room temperature should be on the order of 250 fs [21]. Using shorter pulses and samples with even larger miniband widths, we expect that BO with oscillation frequencies in excess of 10 THz are possible at room temperature.