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Observation of intense nonclassical field of Mandel Q as low as -0.6 in the cavity QED microlaser : 공진기 QED 마이크로레이저에서 만델 Q -0.6의 강한 세기의 비고전광 관측

DC Field Value Language
dc.contributor.advisor안경원-
dc.contributor.author송영훈-
dc.date.accessioned2019-10-21T03:35:46Z-
dc.date.available2019-10-21T03:35:46Z-
dc.date.issued2019-08-
dc.identifier.other000000156835-
dc.identifier.urihttps://hdl.handle.net/10371/162395-
dc.identifier.urihttp://dcollection.snu.ac.kr/common/orgView/000000156835ko_KR
dc.description학위논문(박사)--서울대학교 대학원 :자연과학대학 물리학과,2019. 8. 안경원.-
dc.description.abstractOne of the merits of nonclassical light is a reduced photon number variance below the standard quantum limit. Sub-Poissonian field in a cavity can provide a great improvement in quantum precision measurements via cavity-enhanced light-matter interaction. However, a realization of macroscopic sub-Poissonian field with more than 3dB photon number variance reduction has not been realized. In this thesis, we report the observation of more than 4dB steady-state photon number variance reduction below the standard quantum limit using the cavity-QED microlaser operated with hundreds of atoms. For this work, we investigated the effect of detector dead time on the measurement of the second-order correlation function. Based on the result, we invented so-called dead-time-free Mandel Q measurement method. While the mandel Q is kept below -0.5, the mean photon number of the field was scalable up to 600 which is much larger than analogous experimental results in microwave regime. Furthermore, our study proves that sub-Poisson photon statistics is not deteriorated by multi-atom effects with our experimental conditions. To our best knowledge, this is the first experimental confirmation of validity of extending the single atom model to many atom regime. By including cavity damping effect, we derived a more realistic theory which can exactly describe the photon statistics in the microlaser. Our findings establish the milestone of our proposal of an effective pathway to generate quasi-Fock-state lasing at the macroscopic scale.-
dc.description.abstract비고전광원이 보이는 장점 중 하나는 표준양자한계 미만 수준의 광자 수 분산 감소 효과이다. 공진기 안에서의 sub-Poisson 필드 구현은 공진기로 인해 강화된 빛-물질 상호작용을 이용해 양자정밀측정에서 막대한 개선효과를 가져올 수 있다. 하지만 3dB보다 큰 광자 수 분산 감소효과를 가지는 거시적 크기의 sub-Poisson 필드는 아직까지 구현된 바가 없다. 본 연구에서는 원자수가 수백 개 수준에서 발진하는 공진기-QED 마이크로 레이저를 이용, 정적 상태에서 광자 수 분산이 표준 양자한계 수준보다 4dB 이상으로 작아질 수 있음을 증명했다. 이번 연구를 위해 이차 상관관계 함수 측정 시 광검출기의 불감시간(dead time)이 미치는 영향을 정량분석 하였다. 이 결과를 바탕으로 불감시간에 영향 받지 않는(dead-time-free) Mandel Q 측정 방법을 개발하였다. 이 방법으로 측정된 Mandel Q는 광자수가 600까지 커지는 동안 -0.5 미만을 유지되었는데 광자 수 600은 마이크로웨이브 영역에서의 유사한 실험에서 보여진 것보다 훨씬 크다. 뿐만 아니라 본 연구에서 사용된 실험조건에서는 다원자 효과로 인해 광통계가 영향을 받지 않음을 증명하였다. 이는 단원자 이론 모델을 다원자 영역으로 확장 가능함을 증명한 최초의 실험적 검증이다. 한편, 공진기의 감쇠효과를 동시에 고려하여 마이크로 레이저의 광통계를 정확하게 기술할 수 있는 보다 현실적인 이론 모델을 고안하였다. 이 결과에 근간하여 우리는 거시적 수준의 quasi-Fock-state를 구현하는 방법론을 제안한다.-
dc.description.tableofcontents1 Introduction 1
2 Theory of the microlaser : photon statistics and correlation time 7
2.1 Theoretical model : photon number statistics . . . . . . . . . 7
2.1.1 Quantum microlaser theory . . . . . . . . . . . . . . 7
2.1.2 Semiclassical rate equation model . . . . . . . . . . . 11
2.1.3 Fokker-Planck model . . . . . . . . . . . . . . . . . . 11
2.2 Theoretical model : correlation time . . . . . . . . . . . . . . 14
2.2.1 Rate equation approach . . . . . . . . . . . . . . . . 16
2.2.2 Quantum microlaser theory . . . . . . . . . . . . . . 18
2.3 The relation between correlation time and Mandel Q . . . . 21
2.3.1 Davidovich formalism . . . . . . . . . . . . . . . . . . 21
2.3.2 Approach from quantum microlaser theory . . . . . . 22
2.4 Towards more realistic model . . . . . . . . . . . . . . . . . 25
2.4.1 Introduction to the QTS . . . . . . . . . . . . . . . . 25
2.4.2 Monovelocity, no atomic decay . . . . . . . . . . . . . 27
2.4.3 Inclusion of atomic decay . . . . . . . . . . . . . . . . 29
2.4.4 Inclusion of velocity distribution . . . . . . . . . . . . 29
3 Experimental setup and method 35
3.1 Experimental setup . . . . . . . . . . . . . . . . . . . . . . . 35
3.1.1 Overview of the microlaser setup . . . . . . . . . . . 35
3.1.2 High nesse cavity . . . . . . . . . . . . . . . . . . . 36
3.1.3 Atomic beam . . . . . . . . . . . . . . . . . . . . . . 40
3.1.4 Keeper magnetic eld . . . . . . . . . . . . . . . . . . 42
3.1.5 Laser system . . . . . . . . . . . . . . . . . . . . . . 45
3.1.6 Pump beam . . . . . . . . . . . . . . . . . . . . . . . 50
3.2 Calibration method . . . . . . . . . . . . . . . . . . . . . . . 52
3.2.1 Atomic velocity distribution measurement . . . . . . 52
3.2.2 hni and hNi calibration . . . . . . . . . . . . . . . . 53
3.3 System stabilization . . . . . . . . . . . . . . . . . . . . . . 57
4 Measurement system of the second-order correlation function 65
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4.2 Dead time e ect on a ux of photo detection events . . . . . 71
4.2.1 Light with Poisson photon statistics . . . . . . . . . . 71
4.2.2 Light with non-Poissonian statistics . . . . . . . . . . 73
4.3 Dead-time e ect on the second-order correlation measurement 74
4.4 Experiment and dead time simulation . . . . . . . . . . . . . 77
4.4.1 Counter electronics . . . . . . . . . . . . . . . . . . . 77
4.4.2 Single-photon-counting detectors . . . . . . . . . . . 82
4.4.3 Experiment . . . . . . . . . . . . . . . . . . . . . . . 86
4.4.4 Simulating prolonged dector dead times . . . . . . . . 87
4.5 Result and discussion . . . . . . . . . . . . . . . . . . . . . . 90
4.5.1 Dead time dependence of g(2)(0) . . . . . . . . . . . . 90
4.5.2 Dead time dependence of correlation time c . . . . . 93
4.5.3 Correction methodology to dead time e ect . . . . . 96
4.5.4 Including non-negligible Poissonian background . . . 96
4.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
5 Photon Statistics of the Microlaser 99
5.1 Dead time free Mandel Q with various experimental conditions 99
5.2 Quantum trajectory simulation for cavity damping e ect investigation . . . 107
5.2.1 Collective e ect vs. cavity decay e ect . . . . . . . . 107
5.2.2 QTS results with various conditions . . . . . . . . . . 109
5.3 Modi ed quantum microlaser theory . . . . . . . . . . . . . 116
5.3.1 Overview of QTS results . . . . . . . . . . . . . . . . 116
5.3.2 Modi cation of QMT . . . . . . . . . . . . . . . . . . 119
5.4 Scalable sub-Poisson eld generation in the microlaser . . . . 123
6 Conclusion and Discussion 132
A Conditions for Approximating the Waiting Time Distribution as a Single Exponential 139
B C Programming to Calculate g(2)(t) by Quantum Regression Theorem 141		-
dc.language.isoeng-
dc.publisher서울대학교 대학원-
dc.subjectmicrolaser-
dc.subjectmicromaser-
dc.subjectsub-Poisson-
dc.subjectantibunching-
dc.subjectcavity quantum electrodynamics-
dc.subject.ddc530-
dc.titleObservation of intense nonclassical field of Mandel Q as low as -0.6 in the cavity QED microlaser-
dc.title.alternative공진기 QED 마이크로레이저에서 만델 Q -0.6의 강한 세기의 비고전광 관측-
dc.typeThesis-
dc.typeDissertation-
dc.contributor.AlternativeAuthorYounghoon Song-
dc.contributor.department자연과학대학 물리학과-
dc.description.degreeDoctor-
dc.date.awarded2019-08-
dc.contributor.major양자광학, 원자 분자 물리학-
dc.identifier.uciI804:11032-000000156835-
dc.identifier.holdings000000000040▲000000000041▲000000156835▲-
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