Understanding the Effects of Dephasing on Bloch Wave Interferometry via Temperature Dependent Polarimetry of High-order Sidebands in GaAs

High-order sideband generation is a rich phenomenon in the field of strongly driven quantum matter based on interferometry of Bloch waves. Sidebands are created when electron-hole pairs in a semiconductor produced by a near infrared laser (NIR) are accelerated by an intense terahertz laser. Collision of these pairs leads to emission of sidebands at higher energies than the NIR. Since different Bloch waves can contribute to the creation of any sideband, the polarization of the sidebands is set by the interference of these waves. Previous work has used this polarization to reconstruct the Bloch wavefunctions of holes in GaAs [1].

Because this is a coherent process, understanding the dephasing of the electron-hole pair is key. Dephasing rates are quantities of interest in coherently driven systems. By varying temperature, we can control the dephasing rate and investigate the effects this has on the Bloch wave interferometry. Here, we present the results of temperature dependent HSG polarimetry at temperatures ranging from 25-200 K. We observe that the intensity of these sidebands, but not their polarization, vary with temperature. Analysis of this temperature dependence allows the independent experimental extraction of the dephasing rates of the electron-heavy hole and electron-light hole states of GaAs. This work clears the way for further studies of Bloch wave interferometry in systems with strong dephasing.



References

[1] J. B. Costello, S. D. O’Hara, Q. Wu, et al., Nature. 599, 57-61 (2021).