High-resolution spectroscopy of a quantum dot driven bichromatically by two strong coherent fields

Chris Gustin,Jonathan J Finley,Jonathan R A Müller,Kai Müller,Lukas Hanschke,Malte Kremser,Stephen Hughes,Katarina Boos

doi:10.1103/physrevresearch.3.013044

Abstract

The authors present high resolution spectroscopic measurements and theoretical calculations of a quantum dot driven by two strong coherent lasers, to show a set of Floquet resonances with applications in spectral engineering.

Highlights

Semiconductor quantum dots (QDs) provide an excellent solid-state platform for the coherent control of quantum lightmatter interactions
We include three appendices: in Appendix A, we describe our semianalytical Floquet method for calculating the position of potential spectral lines, as well as include an energy level diagram and perturbative analytical calculations for the specific case of a weak secondary drive dressing a sidepeak of a Mollow triplet created by a strong primary laser; in Appendix B, we present data of experimental characterization of the QD; and in Appendix C, we provide single coherent drive experiments and extract from them an estimate of the phonon coupling strength, which allow us to verify that electron-phonon coupling is qualitatively insignificant in the bichromatic driving regimes studied in the main text
The transition lines are identifiable using semianalytic Floquet theory, with higher-order harmonics required for accurate location of the spectral lines, which is indicative of the regime with two strong components of the bichromatic field

Summary

Introduction

Semiconductor quantum dots (QDs) provide an excellent solid-state platform for the coherent control of quantum lightmatter interactions. Coherent control of quantum systems via continuous wave or pulsed lasers allows for additional tailoring of the emitted photon spectrum by enabling engineered quantum evolution under strong-field interaction, which can manifest in strong-field observables such as the Mollow triplet, Ramsey interference, and Rabi oscillations [15,16,17,18,19,20]. Experiments on bichromatically driven QDs have studied certain regimes of two-color excitation (including “doubly dressed” states), and have revealed an interference-based suppression of the spectral emission line resonant with the exciton frequency, when driven with a strong resonant laser and a second laser detuned to one of the sidebands of the resultant Mollow triplet, as well as a multiphoton AC stark shift of subharmonic resonances [22,37]

Methods

Results

Conclusion