High-resolution nanosecond spectroscopy of even-parity Rydberg excitons in Cu2O

Rogers, Joshua P.; Gallagher, Liam A.P.; Pizzey, Danielle; Pritchett, Jon D.; Adams, Charles S.; Jones, Matthew P.A.; Hodges, Chris; Langbein, Wolfgang; Lynch, Stephen A.

Abstract

We present a study of even-parity Rydberg exciton states in cuprous oxide using second harmonic generation (SHG) spectroscopy. Excitonic states with principal quantum number n = 5 − 12 were excited by nanosecond pulses around 1143 nm. Using time-resolved single-photon counting, the coherently generated second harmonic was isolated both temporally and spectroscopically from inelastic emission due to lower-lying free and bound excitonic states, which included narrow resonances at 1.993 eV associated with a long lifetime of 641 ± 7 µs. The near transform-limited excitation bandwidth enabled high-resolution measurements of the exciton lineshape and position, from which we obtained values for the quantum defects of the S and D excitonic states associated with the appropriate crystal symmetries. Odd-parity P and F excitonic states were also observed, in accordance with predicted quadrupole-allowed two-photon excitation processes. We compared our measurements to conventional one-photon spectroscopy in the same sample, and find that the SHG spectrum is cut off at a lower principal quantum number (n = 12 vs n = 15). We attribute this effect to a combination of spatial inhomogeneities and local heating, and discuss the prospects for observing higher principal quantum number even-parity states in future experiments.

Citation

Rogers, J. P., Gallagher, L. A., Pizzey, D., Pritchett, J. D., Adams, C. S., Jones, M. P., …Lynch, S. A. (2022). High-resolution nanosecond spectroscopy of even-parity Rydberg excitons in Cu2O. Physical Review B, 105(11), Article 115206. https://doi.org/10.1103/physrevb.105.115206

• Journal Article Type: Article
• Acceptance Date: Mar 14, 2022
• Online Publication Date: Mar 31, 2022
• Publication Date: Mar 15, 2022
• Deposit Date: Jun 15, 2022
• Publicly Available Date: Jun 15, 2022
• Journal: Physical Review B
• Print ISSN: 2469-9950
• Electronic ISSN: 2469-9969
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 105
• Issue: 11
• Article Number: 115206
• DOI: https://doi.org/10.1103/physrevb.105.115206
• Public URL: https://durham-repository.worktribe.com/output/1200984