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Descamps T, Liu F, Hangleiter T, Kindel S, Kardynał BE, Bluhm H. Millikelvin confocal microscope with free-space access and high-frequency electrical control. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:083706. [PMID: 39120446 DOI: 10.1063/5.0200889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 07/23/2024] [Indexed: 08/10/2024]
Abstract
Cryogenic confocal microscopy is a powerful method for studying solid state quantum devices such as single photon sources and optically controlled qubits. While the vast majority of such studies have been conducted at temperatures of a few Kelvin, experiments involving fragile quantum effects often require lower operating temperatures. To also allow for electrical dynamic control, microwave connectivity is required. For polarization-sensitive studies, free space optical access is advantageous compared to fiber coupling. Here we present a confocal microscope in a dilution refrigerator providing all the above features at temperatures below 100 mK. The installed high frequency cabling meets the requirements for state-of-the-art spin qubit experiments. As another unique advantage of our system, the sample fitting inside a large puck can be exchanged while keeping the cryostat cold with minimal realignment. Assessing the performance of the instrument, we demonstrate confocal imaging, sub-nanosecond modulation of the emission wavelength of a suitable sample, and an electron temperature of 76 mK. While the instrument was constructed primarily with the development of optical interfaces to electrically controlled qubits in mind, it can be used for many experiments involving quantum transport, solid state quantum optics, and microwave-optical transducers.
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Affiliation(s)
- Thomas Descamps
- JARA-FIT Institute Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, 52074 Aachen, Germany
| | - Feng Liu
- JARA-FIT Institute Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, 52074 Aachen, Germany
| | - Tobias Hangleiter
- JARA-FIT Institute Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, 52074 Aachen, Germany
| | - Sebastian Kindel
- JARA-FIT Institute Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, 52074 Aachen, Germany
| | - Beata E Kardynał
- Peter Grünberg Institute, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Department of Physics, RWTH Aachen University, 52074 Aachen, Germany
| | - Hendrik Bluhm
- JARA-FIT Institute Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, 52074 Aachen, Germany
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MacNeill D, Heikes C, Mak KF, Anderson Z, Kormányos A, Zólyomi V, Park J, Ralph DC. Breaking of valley degeneracy by magnetic field in monolayer MoSe2. PHYSICAL REVIEW LETTERS 2015; 114:037401. [PMID: 25659021 DOI: 10.1103/physrevlett.114.037401] [Citation(s) in RCA: 202] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Indexed: 05/24/2023]
Abstract
Using polarization-resolved photoluminescence spectroscopy, we investigate the breaking of valley degeneracy by an out-of-plane magnetic field in back-gated monolayer MoSe2 devices. We observe a linear splitting of -0.22 meV/T between luminescence peak energies in σ+ and σ- emission for both neutral and charged excitons. The optical selection rules of monolayer MoSe2 couple the photon handedness to the exciton valley degree of freedom; so this splitting demonstrates valley degeneracy breaking. In addition, we find that the luminescence handedness can be controlled with a magnetic field to a degree that depends on the back-gate voltage. An applied magnetic field, therefore, provides effective strategies for control over the valley degree of freedom.
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Affiliation(s)
- David MacNeill
- Department of Physics, Cornell University, Ithaca, New York 14853, USA
| | - Colin Heikes
- Department of Physics, Cornell University, Ithaca, New York 14853, USA
| | - Kin Fai Mak
- Department of Physics, Cornell University, Ithaca, New York 14853, USA and Kavli Institute at Cornell, Cornell University, Ithaca, New York 14853, USA
| | - Zachary Anderson
- Department of Physics, Cornell University, Ithaca, New York 14853, USA
| | - Andor Kormányos
- Department of Physics, University of Konstanz, D-78464 Konstanz, Germany
| | - Viktor Zólyomi
- Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom
| | - Jiwoong Park
- Kavli Institute at Cornell, Cornell University, Ithaca, New York 14853, USA and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - Daniel C Ralph
- Department of Physics, Cornell University, Ithaca, New York 14853, USA and Kavli Institute at Cornell, Cornell University, Ithaca, New York 14853, USA
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