Nonlinear Spectroscopy and Quantum Interferometry : Towards Nonlinear Entangled-Photon Spectroscopy
Hedse, Albin LU
(2026)
- Abstract
- Nonlinear spectroscopy is a powerful method for measuring complex systems with significant inter-state correlations. Even methods such as these are, however, still vulnerable to spectral congestion. One of the proposed methods to enhance the resolution of this already powerful technique is to harness the strong correlations of photon-frequency entanglement. This is easier said than done of course, but this doctoral thesis presents work in nonlinear spectroscopy and towards practical implementations of entangled-photon spectroscopy.
Initially, we present some theoretical analysis of problems which may arise in nonlinear spectroscopy when pulse overlap is an issue. This is carried out in Paper I, which also numerically quantifies a... (More) - Nonlinear spectroscopy is a powerful method for measuring complex systems with significant inter-state correlations. Even methods such as these are, however, still vulnerable to spectral congestion. One of the proposed methods to enhance the resolution of this already powerful technique is to harness the strong correlations of photon-frequency entanglement. This is easier said than done of course, but this doctoral thesis presents work in nonlinear spectroscopy and towards practical implementations of entangled-photon spectroscopy.
Initially, we present some theoretical analysis of problems which may arise in nonlinear spectroscopy when pulse overlap is an issue. This is carried out in Paper I, which also numerically quantifies a fundamental theoretical limitation that pulse overlap presents, especially for short-lived signals.
We then go on to experimental data analysis of the origins of coherent beatings and the size-dependence of primarily biexciton binding energies in CdSe quantum dots. These are covered in Papers II and III respectively.
Finally, we perform an investigation of the possible upper bounds of an entangled-two photon absorption cross-section. Claims of strong quantum advantages in low-flux regimes have warranted further observation, and in examining them we are taking the first steps towards nonlinear entangled spectroscopy. This is done through use of a Franson interferometer, used here in a novel way by performing delay-dependent coincidence measurements for the purpose of obtaining an upper bound on entangled two-photon absorption cross-sections. This work is covered in Paper IV. We then discuss possible future directions for entangled-photon spectroscopy and the forms it can take. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/4f9cff60-36cb-4117-88c7-262adafed266
- author
- Hedse, Albin
LU
- supervisor
-
- Tönu Pullerits LU
- Andreas Wacker LU
- opponent
-
- Dr. Kowalewski, Markus, Stockholm University, Department of Physics, Molecular Quantum Dynamics and Spectroscopy
- organization
- publishing date
- 2026
- type
- Thesis
- publication status
- published
- subject
- keywords
- Nonlinear spectroscopy, Time-frequency entanglement, Two-photon absorption, Measurement artifacts, Franson interferometry, Kvantsammanflätning, Fransoninterferometri, Ickelinjär spektroskopi, Tvåfotonsabsorption, Mätningsartefakter
- pages
- 91 pages
- publisher
- Media-Tryck, Lund University, Sweden
- defense location
- Kemicentrum, Sal F. Join via zoom: https://lu-se.zoom.us/j/7513296734
- defense date
- 2026-10-30 09:00:00
- ISBN
- 978-91-6858-017-3
- 978-91-6858-018-0
- language
- English
- LU publication?
- yes
- id
- 4f9cff60-36cb-4117-88c7-262adafed266
- date added to LUP
- 2026-10-06 10:33:12
- date last changed
- 2026-10-09 12:40:49
@phdthesis{4f9cff60-36cb-4117-88c7-262adafed266,
abstract = {{Nonlinear spectroscopy is a powerful method for measuring complex systems with significant inter-state correlations. Even methods such as these are, however, still vulnerable to spectral congestion. One of the proposed methods to enhance the resolution of this already powerful technique is to harness the strong correlations of photon-frequency entanglement. This is easier said than done of course, but this doctoral thesis presents work in nonlinear spectroscopy and towards practical implementations of entangled-photon spectroscopy.<br/>Initially, we present some theoretical analysis of problems which may arise in nonlinear spectroscopy when pulse overlap is an issue. This is carried out in Paper I, which also numerically quantifies a fundamental theoretical limitation that pulse overlap presents, especially for short-lived signals.<br/>We then go on to experimental data analysis of the origins of coherent beatings and the size-dependence of primarily biexciton binding energies in CdSe quantum dots. These are covered in Papers II and III respectively.<br/>Finally, we perform an investigation of the possible upper bounds of an entangled-two photon absorption cross-section. Claims of strong quantum advantages in low-flux regimes have warranted further observation, and in examining them we are taking the first steps towards nonlinear entangled spectroscopy. This is done through use of a Franson interferometer, used here in a novel way by performing delay-dependent coincidence measurements for the purpose of obtaining an upper bound on entangled two-photon absorption cross-sections. This work is covered in Paper IV. We then discuss possible future directions for entangled-photon spectroscopy and the forms it can take.}},
author = {{Hedse, Albin}},
isbn = {{978-91-6858-017-3}},
keywords = {{Nonlinear spectroscopy; Time-frequency entanglement; Two-photon absorption; Measurement artifacts; Franson interferometry; Kvantsammanflätning; Fransoninterferometri; Ickelinjär spektroskopi; Tvåfotonsabsorption; Mätningsartefakter}},
language = {{eng}},
publisher = {{Media-Tryck, Lund University, Sweden}},
school = {{Lund University}},
title = {{Nonlinear Spectroscopy and Quantum Interferometry : Towards Nonlinear Entangled-Photon Spectroscopy}},
url = {{https://lup.lub.lu.se/search/files/262554703/Avhandling_Albin_Hedse_LUCRIS.pdf}},
year = {{2026}},
}