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A chirped, pulsed laser system and magneto-optical trap for rubidium

A chirped, pulsed laser system and magneto-optical trap for rubidium
A chirped, pulsed laser system and magneto-optical trap for rubidium
This thesis covers the construction and characterisation of a magneto-optical trap (MOT) for 85Rb from the very beginning. It details both the optical and mechanical aspects from laser diode assembly, tuning and stabilisation to the preparation and assembly of the vacuum system. The MOT construction forms the first goal of the project, the second was to develop a laser system capable of producing custom programmable, amplitude modulated and frequency chirped pulses (on the tens of microseconds timescale) from a continuous wave source. This involved developing software and computer control for several arbitrary signal generators linked to drivers for acousto-optic and electro-optic modulators. This chirped, pulsed laser system will be used to perform state manipulations on the 85Rb MOT cloud using two-photon Raman transitions in an adiabatic rapid passage regime. The chirped pulse system was initially tested with a rubidium vapour cell in an attempt to perform atomic interferometry that would produce spatial interference fringes along the length of the cell. However, due to the beam power requirements, the beam diameter together with the large Doppler shift at room temperature meant these fringes were not seen and so the vapour cell was replaced with the cold atom cloud in the MOT. Two-photon experiments were attempted with the MOT cloud using the chirped pulse system, however despite greatly improved laser power and detection eficiency, the signal indicating ground state population transfer via a two-photon interaction was not seen. The results indicate that the hyperfine-ground state splitting frequency has been shifted due to the proximity of the ion pump magnet to the vacuum system. Presently, efforts are being directed towards searching for the correct frequency.
Patel, Sunil
2a69771a-9c96-4684-8c95-e46e72cacf87
Patel, Sunil
2a69771a-9c96-4684-8c95-e46e72cacf87
Freegarde, Timothy
01a5f53b-d406-44fb-a166-d8da9128ea7d

Patel, Sunil (2009) A chirped, pulsed laser system and magneto-optical trap for rubidium. University of Southampton, School of Physics and Astronomy, Doctoral Thesis, 222pp.

Record type: Thesis (Doctoral)

Abstract

This thesis covers the construction and characterisation of a magneto-optical trap (MOT) for 85Rb from the very beginning. It details both the optical and mechanical aspects from laser diode assembly, tuning and stabilisation to the preparation and assembly of the vacuum system. The MOT construction forms the first goal of the project, the second was to develop a laser system capable of producing custom programmable, amplitude modulated and frequency chirped pulses (on the tens of microseconds timescale) from a continuous wave source. This involved developing software and computer control for several arbitrary signal generators linked to drivers for acousto-optic and electro-optic modulators. This chirped, pulsed laser system will be used to perform state manipulations on the 85Rb MOT cloud using two-photon Raman transitions in an adiabatic rapid passage regime. The chirped pulse system was initially tested with a rubidium vapour cell in an attempt to perform atomic interferometry that would produce spatial interference fringes along the length of the cell. However, due to the beam power requirements, the beam diameter together with the large Doppler shift at room temperature meant these fringes were not seen and so the vapour cell was replaced with the cold atom cloud in the MOT. Two-photon experiments were attempted with the MOT cloud using the chirped pulse system, however despite greatly improved laser power and detection eficiency, the signal indicating ground state population transfer via a two-photon interaction was not seen. The results indicate that the hyperfine-ground state splitting frequency has been shifted due to the proximity of the ion pump magnet to the vacuum system. Presently, efforts are being directed towards searching for the correct frequency.

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Published date: March 2009
Organisations: University of Southampton

Identifiers

Local EPrints ID: 66245
URI: https://eprints.soton.ac.uk/id/eprint/66245
PURE UUID: 53671aad-c52d-4f97-9c77-3e2a1a1b583c
ORCID for Timothy Freegarde: ORCID iD orcid.org/0000-0002-0680-1330

Catalogue record

Date deposited: 16 Jun 2009
Last modified: 06 Jun 2018 12:45

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Contributors

Author: Sunil Patel
Thesis advisor: Timothy Freegarde ORCID iD

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