1. Nonradiative Quantum Coherences in Semiconductors Hailin Wang, University of Oregon, DMR-0502738
While storage of classical information is a well- established technology, storage of quantum information remains a scientific and technological challenge. Recently, it has been proposed that electron spin coherence in atomic vapors can be used as quantum memory for photons. This project explores the possibility of extending this idea to semiconductors. The proposed research includes detailed studies of coherent nonlinear optical phenomena induced by electron spin coherence in semiconductors and the use of electron spin coherence in a semiconductor waveguide to store quantum information of light.
Phys. Rev. Lett. 92, (2004).
Phys. Rev. B72, (2005).
For the above figure, we measured the absorption of a probe beam as a function of the detuning between the probe and the pump. The pump and probe beams together induce a coherent superposition of electron spins in the waveguide. The coherent quantum superposition reduces the absorption of the probe beam through destructive quantum interference. The type of processes can in principle be used for storing quantum information of photons in an optical medium.
Electron spin coherence excited by two laser beams in a GaAs waveguide induces a sharp resonance in the transmission spectrum through destructive quantum interference. The spin coherence can be potentially used for quantum information storage.

2. Nonradiative Quantum Coherences in Semiconductors Hailin Wang, University of Oregon, DMR-0502738
Education:
Seven graduate students and two undergraduate students contributed to this and previous DMR projects. Four students have graduated with PhD in Physics in the past five years. Mark Phillips is now a staff member at Sandia National Lab, Scott Lacey is now an assistant professor at Franklin and Marshall College, Phedon Palinginis is now a postdoc at UC Berkeley, Xudong Fan is now an assistant professor at University of Missouri. Sasha Kruger, Susanta Sarkar, and Yumin Shen plan to graduate in a year.
Broad Impact:
Research conducted in this program provides excellent training for graduate and undergraduate students in semiconductor physics, laser physics, nanotechnology, and information technology, preparing them for careers in academe, industry, or government.
This project develops the basic scientific understanding as well as the technology for storing quantum mechanical information instead of classical information in semiconductor materials.