Optical Manipulation of Electron Spin Coherence by Selective Control of the Nuclear Magnetic Field

A pump-probe spectroscopy model utilizing two pump pulses within the repetition rate of a mode-locked laser is developed to selectively control dynamic nuclear polarization (DNP) by the optical Stark effect (OSE) and the subsequent buildup of nuclear spin polarization. The selective control of DNP is achieved by choosing a temporal separation between the two pump pulses in a manner such that one may choose where in the Larmor precession the electron spin polarization rotates into the direction of an applied magnetic field. Choosing where in the Larmor precession the electron spin rotates provides finer control over the strength of the OSE-induced electron-nuclear spin interactions and subsequent control of the nuclear magnetic field (i.e., the Overhauser field) buildup. An outline of a computation model corroborated with experimental data will be presented. The presented material demonstrates manipulation of electron spin coherences and the nuclear-induced frequency focusing effect that are unattainable in a one-pump model. Simply put, the two-pump model outlined in this presentation offers versatility for manipulating electron spin coherences, thereby providing a foundational approach for controlling the OSE-induced electron-nuclear spin interactions.