Superconducting Devices in Quantum Optics (eBook)

Preface 6
Contents 9
Contributors 11
Part I Superconducting Single PhotonDetectors: Technology and Applications 14
1 Superconducting Nanowire Architectures for Single Photon Detection 15
1.1 Introduction 16
1.2 Performance Metrics for Photon Counting Detectors 16
1.2.1 Detection Efficiency 16
1.2.2 Dark Count Rate 17
1.2.3 Timing Jitter 18
1.2.4 Recovery Time 18
1.3 Superconducting Nanowire Single Photon Detectors (SNSPDs) 19
1.3.1 Photodetection Mechanism 20
1.3.2 Detection Efficiency and Constrictions 20
1.3.3 Speed Limit and Latching 22
1.3.4 Mid-IR Detection 24
1.3.5 Performance Trade-Offs 25
1.4 Multi-Nanowire Detector Architectures 26
1.4.1 Superconducting Nanowire Avalanche Photodetectors (SNAPs) 26
1.4.2 Parallel- and Series-Nanowire Detectors (PNDs, SNDs) 33
1.4.3 Row-Column SNSPD Arrays 36
1.5 Conclusions 38
References 38
2 Superconducting Transition Edge Sensors for Quantum Optics 43
2.1 Introduction 43
2.2 The Optical Transition Edge Sensor 45
2.2.1 TES Operation 45
2.2.2 TES Optimization 49
2.2.3 Detector Characterization 55
2.3 Applications of the Optical Transition Edge Sensor 58
2.3.1 Key Experiments in Quantum Optics 58
2.4 Integration of Optical TES on Waveguide Structures 63
2.4.1 On-Chip Transition Edge Sensor 63
2.4.2 A New Experimental Tool: On-Chip Mode-Matched Photon Subtraction 66
2.4.3 On-Chip Detector Calibration 67
2.5 Outlook 68
References 69
3 Waveguide Superconducting Single- and Few-Photon Detectors on GaAs for Integrated Quantum Photonics 73
3.1 Introduction 73
3.1.1 Integrated Quantum Photonics 74
3.1.2 GaAs-Based Quantum Photonic Integrated Circuits 75
3.1.3 Nanowire Detectors on GaAs 76
3.2 Fabrication of Nanowire Waveguide Detectors on GaAs 77
3.2.1 Deposition of NbN Thin Films on GaAs 77
3.2.2 Detector Nanofabrication 79
3.3 Measurement Setup for Waveguide Detectors 80
3.4 Waveguide Single-Photon Detectors 81
3.4.1 Design 81
3.4.2 Results 83
3.5 Waveguide Photon-Number-Resolving Detectors on GaAs 86
3.5.1 Photon-Number-Resolving (PNR) Detectors Using Superconducting NbN Nanowires 86
3.5.2 Design of WPNRDs 87
3.5.3 Experimental Results on WPNRDs 89
3.6 Conclusions 91
References 92
4 Waveguide Integrated Superconducting Nanowire Single Photon Detectors on Silicon 96
4.1 Introduction 96
4.2 Single Photon Detection in Superconducting Nanowires 99
4.3 Silicon Photonic Circuits for SNSPD Integration 101
4.4 Silicon Nitride Photonic Circuits for Broadband Single Photon Applications 102
4.5 Absorption Engineering of Superconducting Nanowire Devices 104
4.6 Waveguide Integrated Single Photon Detectors 106
4.7 Applications 107
4.7.1 Ballistic Photon Transport in Silicon Microring Resonators 108
4.7.2 Optical Time Domain Reflectometry 110
4.7.3 Outlook on Applications of Waveguide Integrated SNSPDs 112
4.8 Conclusions 112
References 113
5 Quantum Information Networks with Superconducting Nanowire Single-Photon Detectors 117
5.1 Introduction 117
5.2 Quantum Key Distribution Using SNSPDs 118
5.2.1 Outline of the Tokyo QKD Network 119
5.2.2 Decoy State BB84 Protocol System with SNSPDs 120
5.2.3 DPS-QKD System with SNSPDs 123
5.2.4 Demonstration of Secure Network Operation 124
5.2.5 Characterization of Field Practical Fibers Using a SNSPD 125
5.3 Characterization of Single Photon Sources with SNSPDs 131
5.3.1 Detection of Heralded Single Photon Emission Using Twin SNSPDs 131
5.3.2 Demonstration of an Entangled Photon Source with SNSPDs 133
5.3.3 Demonstration of Interference Between Two Independent Single Photon Sources Using SNSPDs 135
5.3.4 Photon Source Characterization: Conclusions 135
5.4 Quantum Interface Technology Enabled by SNSPDs 136
5.4.1 Quantum Interface for the Coherent Wavelength Conversion of a Single Photon 137
5.4.2 Experiments with a Waveguide PPLN Crystal 138
5.4.3 HOM Interference Over the Quantum Interface with SNSPD 140
5.4.4 Quantum Interface Technology: Summary 140
5.5 Conclusions 141
References 142
Part II Superconducting Quantum Circuits:Microwave Photon Detection,Feedback and Quantum Acoustics 146
6 Microwave Quantum Photonics 147
6.1 Introduction 147
6.2 Key Ingredients of Superconducting Circuit 148
6.2.1 Superconducting Artificial Atoms 148
6.2.2 Coplanar Transmission Lines and Microwave Resonators 152
6.2.3 Amplifiers and Detection Devices 153
6.3 Interaction Between `Atoms' and Microwaves 154
6.3.1 Circuit QED 154
6.3.2 Applications: Measurement of Microwave Photons 156
6.3.3 Applications: Generation of Microwave Photons 166
6.4 Conclusions 167
References 168
7 Weak Measurement and Feedback in Superconducting Quantum Circuits 171
7.1 Introduction 171
7.2 Generalized Measurements 172
7.2.1 Indirect Measurements 173
7.2.2 Continuous Measurement 175
7.3 Quantum Measurements in the cQED Architecture 176
7.3.1 Dispersive Measurements 178
7.3.2 Parametric Amplification 179
7.3.3 Weak Measurement and Backaction 180
7.4 Quantum Trajectories 182
7.4.1 Continuous Quantum Measurement 182
7.4.2 Unitary Evolution 184
7.4.3 The Statistics of Quantum Trajectories 185
7.4.4 Time-Symmetric State Estimation 186
7.5 Analog Feedback Stabilization: Rabi Oscillations 187
7.5.1 Weak Monitoring of Rabi Oscillations 187
7.6 Conclusion 191
References 191
8 Digital Feedback Control 194
8.1 Digital Feedback Control in Quantum Computing 195
8.1.1 Classification of Quantum Feedback 195
8.1.2 Protocols Using Digital Feedback 196
8.1.3 Experimental Realizations of Digital Feedback 197
8.1.4 Concepts in Digital Feedback 198
8.1.5 Closing the Loop in cQED 199
8.2 High-Fidelity Projective Readout of Transmon Qubits 199
8.2.1 Experimental Setup 199
8.2.2 Characterization of JPA-Backed Qubit Readout and Initialization 200
8.2.3 Repeated Quantum Nondemolition Measurements 202
8.3 Digital Feedback Controllers 205
8.4 Fast Qubit Reset Based on Digital Feedback 208
8.4.1 Passive Qubit Initialization to Steady State 208
8.4.2 Qubit Reset Based on Digital Feedback 209
8.4.3 Characterization of the Reset Protocol 209
8.4.4 Speed-Up Enabled by Fast Reset 211
8.5 Deterministic Entanglement by Parity Measurement and Feedback 212
8.5.1 Two-Qubit Parity Measurement 213
8.5.2 Engineering the Cavity as a Parity Meter 213
8.5.3 Two-Qubit Evolution During Parity Measurement 215
8.5.4 Probabilistic Entanglement by Measurement and Postselection 216
8.5.5 Deterministic Entanglement by Measurement and Feedback 218
8.6 Conclusion 219
References 219
9 Quantum Acoustics with Surface Acoustic Waves 224
9.1 Introduction 225
9.2 Surface Acoustic Waves, Materials and Fabrication 227
9.2.1 Materials for Quantum SAW Devices 227
9.2.2 Fabrication of SAW Devices 229
9.3 Theory 230
9.3.1 Classical IDT Model 230
9.3.2 Semiclassical Theory for SAW-Qubit Interaction 233
9.3.3 Quantum Theory for Giant Atoms 235
9.4 SAW Resonators for Quantum Devices 238
9.4.1 Resonator Quality Factors at Low Temperature 238
9.4.2 ZnO for High Q SAW Devices at Low Temperature 240
9.5 SAW-Qubit Interaction in Experiment 242
9.6 Future Directions 246
9.6.1 In-Flight Manipulation 247
9.6.2 Coupling to Optical Photons 247
9.6.3 Ultrastrong Coupling Between SAWs and Artificial Atoms 247
9.6.4 Large Atoms 248
9.6.5 SAW Resonators 248
9.6.6 Analogues of Quantum Optics 249
9.7 Conclusions 249
References 249
Index 252