Magnetic Field and Temperature Dependence of Decoherence in a High Mobility Landau Quantized 2DEG

We apply a perpendicular magnetic field to a high mobility ($\mu=3.4\times 10^{6}$ cm$^{2}$ V$^{-1}$ s$^{-1}$) two dimensional electron gas (2DEG) which splits the Fermi surface into a spectrum of Landau levels (LL). The highest filled and lowest unfilled LLs are coherently coupled by an incident THz pulse. The time required for carriers in this superposition state to become out of phase is the decoherence time. The focus of our work is to measure this decoherence time over a wide range of temperatures (0.4 K-100 K) and magnetic fields (1.25 T-17.5 T). Using THz time-domain spectroscopy (TTDS), we map the decoherence as a function of B and T. This talk will review previous work done at 0.4 K and 1.25 T; furthermore, we will discuss current work being done to increase our B dependence to 17.5 T using superconducting magnet 3 at the National High Magnetic Field Lab at Florida State University. This work utilizes a novel \emph{reflection} TTDS system.