### HMC Physics Colloquium

Tuesdays at 16:30 in Shanahan Center for Teaching and Learning, Room B460

## Kai-Mei Fu

Hewlett Packard Labs

Optical Spintronics for Quantum Information Processing and Magnetic Sensing

March 2, 2010

The optical detection and control of solid-state spins has exciting applications in the fields of quantum information processing and magnetic sensing. In the first part of the talk I will show how optical pulses can be used to measure the three fundamental relaxation times of electrons bound to donors in GaAs: population relaxation $$T_1$$, inhomogeneous dephasing $$T_2^*$$, and homogeneous dephasing $$T_2$$. These relaxation rates can be used to determine the potential a spin system will have as a qubit in a quantum information application. In the second part of the talk I discuss how the unique optical and spin properties of nitrogen-vacancy centers in diamond can be used to engineer a highly sensitive magnetic sensor. A diamond-based magnetic sensing surface is demonstrated and biological applications for this system are discussed.