Lasersko hlađenje pomoću frekventnog češlja i optičkog rezonatora

master's thesis

• Title (english): Laser cooling using a frequency comb and an optical cavity
• Author: Bruno Babić
• Mentor: Damir Aumiler (mentor)
• Mentor: Marko Tomislav Cvitaš (komentor)
• Committee member: Marko Tomislav Cvitaš (predsjednik povjerenstva)
• Committee member: Damir Aumiler (član povjerenstva)
• Committee member: Marinko Jablan (član povjerenstva)
• Committee member: Vedran Đerek (član povjerenstva)
• Committee member: Hrvoje Buljan (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2022-07-20, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

U ovome diplomskom radu eksperimentalno se istraživala interakcija hladnog oblaka atoma rubidija 87Rb sa svjetlosti unutar optičkog rezonatora visoke finese, te mogućnost rezonatorskog hlađenja u procesima analognim sub-Dopplerovom hlađenju atoma pomoću kontinuiranih lasera. Atomski oblak, predhlađen na sub-Dopplerove temperature, pomoću standardnih tehnika hlađenja s kontinuiranim laserima u magneto optičkoj stupici, uveden je u centar optičkog rezonatora a potom je ispušten iz stupice kako bi slobodno interagirao s optičkim potencijalom unutar rezonatora. Interakcija je ispitivana slikanjem fluorescencije oblaka u metodi vremena proleta. Ispitivanja interakcije u režimu longitudinalnog pumpanja s kontinuiranim laserom, blizu frekvencije prijelaza atoma, pokazala su efekt djelomičnog zatočenja atoma iz oblaka, no neovisnost o pomaku frekvencije lasera od linije rezonatora upućuje na odsustvo dodatnog efekta hlađenja. Eksperiment je ponovljen s pumpanjem rezonatora frekventnim češljem blizu atomske rezonancije rubidija. Opažen je potpis interakcije atoma u rezonatoru i frekventnog češlja, no u fluorescenciji oblaka nije zabilježen efekt hlađenja atoma multimodnim pobuđenjem rezonatora frekventnim češljem.

Abstract (english)

In this thesis, we experimentally tested the interactions of cold clouds of rubidium atoms 87Rb with light inside a high-fineness optical resonator, and the possibility of resonator cooling in processes analogous to sub-Doppler cooling of atoms using continuous wave lasers. An atomic cloud, pre-cooled to sub-Doppler temperatures, using standard continuous laser cooling techniques in a magneto-optical trap, was introduced into the center of the optical resonator and then released from the trap to interact freely with the optical potential inside the resonator. The interaction was examined by imaging of cloud fluorescence in the time of flight method. Tests of the interaction, in the longitudinal pumping regime, with a continuous wave laser near atomic resonance have shown the effect of partial trapping of atoms from the cloud, but lack of sensitivity on laser detuning from the resonator line indicates the absence of additional cooling effects. The experiment was repeated by pumping the cavity with a frequency comb with frequency near rubidium atomic resonance. Signature of comb-atom interaction in the cavity was recorded, but no cooling effect on the atoms by multimode comb excitation of the cavity was observed in the cloud fluorescence.

• Keywords: Dopplerov hlađenje; radijativna sila; magnetooptička stupica; sub- Dopplerovo hlađenje; hlađenje gradijentom polarizacije; rubidijevi atomi; optički rezonator; dipolna sila; dressed stanja; hlađenje u optičkom rezonatoru; sub Doppler temperatura; frekventni češalj; femtosekundni laser; frekventna stabilizacija
• Keywords (english): Doppler cooling; radiation force; magneto-optical trap; sub-Doppler cooling; polarization gradient cooling; rubidium atoms; optical cavity; dipole force; dressed states; cavity cooling; sub-Doppler temperature; frequency comb; femtosecond laser; frequency stabilization
• Language: croatian
• URN:NBN: urn:nbn:hr:217:315542
• Study programme: Title: Physics; specializations in: Research; Course: Research; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra fizike (magistar/magistra fizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2022-12-20
• Created on: 2022-09-07 08:35:00