The conductance through a quantum point was discovered in 1988 to be a multiple of the quantum conductance 2e2/h. This quantum behavior may have an important impact on the development of future generation of electronic devices. The focus of this project is to study the interaction between far- infrared photons and electrons in quantum point contacts. It is expected that this conductance can be modulated by a small-amplitude far-infrared radiation. By absorbing photons, the electrons can raise their energies to above the level of a subband in the quantum point contact and contribute to conduction. This effect is similar to photon-assisted tunneling in superconducting tunnel junctions. The result of this research may substantially improve our understanding of the quantum transport phenomena, and the interaction between electrons and photons in the quantum transport processes. If the effect is verified experimentally, novel long-wavelength optoelectronic devices, such as optically controlled switches and modulators, photon detectors and heterodyne mixers, can be constructed.
