Coherent oscillations

J. Feldmann, K. Leo, J. Shah, D. A. B. Miller, J. E. Cunningham, T. Meier, G. vonPlessen, A. Schulze, P. Thomas, and S. Schmitt-Rink, “Optical investigation of Bloch oscillations in a semiconductor superlattice,” Phys. Rev. B 46, 7252‑7255 (1992)

H. G. Roskos, M. C. Nuss, J. Shah, K. Leo, D. A. B. Miller, A. M. Fox, S. Schmitt-Rink, and K. Kohler, “Coherent submillimeter- wave emission from charge oscillations in a double-well potential,” Phys. Rev. Lett. 68, 2216‑2219 (1992).