Photo of Audrina Sewal

Audrina Sewal

QF Intern Summer 2021
Santa Barbara City College, UC Berkeley

Major: Physics
Mentors: Seamus O'Hara, Professor Mark Sherwin

Experimental Reconstruction of Bloch Wavefunctions through High-Order Sideband Generation

Solid state quantum computing requires unprecedented control over electron wavefunctions within nanostructured materials. Therefore, it is important to characterize the quantum nature of Bloch wavefunctions. This can be done through a process known as High-order sideband generation (HSG). HSG is an optical process in semiconductors where a weak near-infrared (NIR) laser and a strong terahertz (THz) laser interact. Here we present data using gallium arsenide (GaAs). The NIR laser generates electron-hole pairs, with two species of holes: light holes (LH) and heavy holes (HH). The electron and hole are driven apart and recollide to emit sideband photons. The Bloch waves that are associated with these LH and HH interfere through the influence of the THz field, generated by the free-electron laser (FEL). This interference is imprinted on the polarization state and angular momentum of the light generated from these sidebands. By measuring this polarization, we reconstruct the Bloch wavefunction. Current experiments investigate how this interference changes with varying THz field strength.