Coherent transmission of light through a cold atomic cloud

We study the coherent transmission of light through cold strontium atomic clouds, using the narrow intercombination line. In the first part of the thesis, the cooperative emission in the coherent transmission is studied experimentally. By applying fast changes to the incident probe field, flashes o...

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Bibliographic Details
Main Author: Kwong, Chang Chi
Other Authors: David Wilkowski
Format: Thesis
Language:English
Published: 2017
Subjects:
Online Access:http://hdl.handle.net/10356/69897
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author Kwong, Chang Chi
author2 David Wilkowski
author_facet David Wilkowski
Kwong, Chang Chi
author_sort Kwong, Chang Chi
collection NTU
description We study the coherent transmission of light through cold strontium atomic clouds, using the narrow intercombination line. In the first part of the thesis, the cooperative emission in the coherent transmission is studied experimentally. By applying fast changes to the incident probe field, flashes of light are observed in the forward direction. The peak intensity of the flashes can be much larger than the incident intensity. These flashes are called superflashes. Due to cooperative effect, the time scale of the flashes are shortened with respect to the single scatterer lifetime. By packing these flashes, we generate a pulse train with short repetition time, where the dynamics can almost be fully governed by cooperative effect. The effect of atomic density on the coherent transmission of light is also studied theoretically and numerically. The effective refractive index of the cloud is calculated up to the second order in atomic density. It is eventually validated with a numerical simulation of the coherent light transmission. The second part of the thesis focuses on the effect of magnetic field on the coherent transmission of light. The strontium intercombination line has a sensitivity in the milligauss regime, which is the typical value of stray magnetic field in the lab. An active magnetic field control system is implemented to cancel the low frequency and AC 50~Hz stray magnetic field. Using this control system, we study the nonlinear magneto-optical rotation (NMOR) effect due to a high intensity light field transmitting through a dilute and thin cloud of strontium atom. Interestingly, at sufficiently high cloud temperature, the NMOR effect can have a higher sensitivity to the magnetic field, compared to its linear counterpart at the same cloud temperature.
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spelling ntu-10356/698972023-02-28T23:39:33Z Coherent transmission of light through a cold atomic cloud Kwong, Chang Chi David Wilkowski School of Physical and Mathematical Sciences Rainer H. Dumke DRNTU::Science::Physics::Optics and light DRNTU::Science::Physics::Atomic physics We study the coherent transmission of light through cold strontium atomic clouds, using the narrow intercombination line. In the first part of the thesis, the cooperative emission in the coherent transmission is studied experimentally. By applying fast changes to the incident probe field, flashes of light are observed in the forward direction. The peak intensity of the flashes can be much larger than the incident intensity. These flashes are called superflashes. Due to cooperative effect, the time scale of the flashes are shortened with respect to the single scatterer lifetime. By packing these flashes, we generate a pulse train with short repetition time, where the dynamics can almost be fully governed by cooperative effect. The effect of atomic density on the coherent transmission of light is also studied theoretically and numerically. The effective refractive index of the cloud is calculated up to the second order in atomic density. It is eventually validated with a numerical simulation of the coherent light transmission. The second part of the thesis focuses on the effect of magnetic field on the coherent transmission of light. The strontium intercombination line has a sensitivity in the milligauss regime, which is the typical value of stray magnetic field in the lab. An active magnetic field control system is implemented to cancel the low frequency and AC 50~Hz stray magnetic field. Using this control system, we study the nonlinear magneto-optical rotation (NMOR) effect due to a high intensity light field transmitting through a dilute and thin cloud of strontium atom. Interestingly, at sufficiently high cloud temperature, the NMOR effect can have a higher sensitivity to the magnetic field, compared to its linear counterpart at the same cloud temperature. ​Doctor of Philosophy (SPMS) 2017-03-31T01:17:29Z 2017-03-31T01:17:29Z 2017 Thesis Kwong, C. C. (2017). Coherent transmission of light through a cold atomic cloud. Doctoral thesis, Nanyang Technological University, Singapore. http://hdl.handle.net/10356/69897 10.32657/10356/69897 en 321 p. application/pdf
spellingShingle DRNTU::Science::Physics::Optics and light
DRNTU::Science::Physics::Atomic physics
Kwong, Chang Chi
Coherent transmission of light through a cold atomic cloud
title Coherent transmission of light through a cold atomic cloud
title_full Coherent transmission of light through a cold atomic cloud
title_fullStr Coherent transmission of light through a cold atomic cloud
title_full_unstemmed Coherent transmission of light through a cold atomic cloud
title_short Coherent transmission of light through a cold atomic cloud
title_sort coherent transmission of light through a cold atomic cloud
topic DRNTU::Science::Physics::Optics and light
DRNTU::Science::Physics::Atomic physics
url http://hdl.handle.net/10356/69897
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