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Khvorost T, Wójcik P, Chang C, Calvillo M, Dickerson C, Lao G, Hudson ER, Krylov AI, Alexandrova AN. Dual Optical Cycling Centers Mounted on an Organic Scaffold: New Insights from Quantum Chemistry Calculations and Symmetry Analysis. J Phys Chem Lett 2024; 15:5665-5673. [PMID: 38767654 DOI: 10.1021/acs.jpclett.4c00623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Molecules cooled to ultracold temperatures are desirable for applications in fundamental physics and quantum information science. However, cooling polyatomic molecules with more than six atoms has not yet been achieved. Building on the idea of an optical cycling center (OCC), a moiety supporting a set of localized and isolated electronic states within a polyatomic molecule, molecules with two OCCs (bi-OCCs) may afford better cooling efficiency by doubling the photon scattering rate. By using quantum chemistry calculations, we assess the extent of the coupling of the two OCCs with each other and the molecular scaffold. We show that promising coolable bi-OCC molecules can be proposed by following chemical design principles.
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Affiliation(s)
- Taras Khvorost
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Paweł Wójcik
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Cecilia Chang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Mia Calvillo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Claire Dickerson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Guanming Lao
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Eric R Hudson
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
- Challenge Institute for Quantum Computation, University of California, Los Angeles, California 90095, United States
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Anastassia N Alexandrova
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
- Challenge Institute for Quantum Computation, University of California, Los Angeles, California 90095, United States
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Zhu GZ, Lao G, Dickerson CE, Caram JR, Campbell WC, Alexandrova AN, Hudson ER. Extending the Large Molecule Limit: The Role of Fermi Resonance in Developing a Quantum Functional Group. J Phys Chem Lett 2024; 15:590-597. [PMID: 38198595 DOI: 10.1021/acs.jpclett.3c03177] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Polyatomic molecules equipped with optical cycling centers (OCCs), enabling continuous photon scattering during optical excitation, are exciting candidates for advancing quantum information science. However, as these molecules grow in size and complexity, the interplay of complex vibronic couplings on optical cycling becomes a critical but relatively unexplored consideration. Here, we present an extensive exploration of Fermi resonances in large-scale OCC-containing molecules using high-resolution dispersed laser-induced fluorescence and excitation spectroscopy. These resonances manifest as vibrational coupling leading to intensity borrowing by combination bands near optically active harmonic bands, which require additional repumping lasers for effective optical cycling. To mitigate these effects, we explore altering the vibrational energy level spacing through substitutions on the phenyl ring or changes in the OCC itself. While the complete elimination of vibrational coupling in complex molecules remains challenging, our findings highlight significant mitigation possibilities, opening new avenues for optimizing optical cycling in large polyatomic molecules.
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Affiliation(s)
- Guo-Zhu Zhu
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Guanming Lao
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Claire E Dickerson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Justin R Caram
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
| | - Wesley C Campbell
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
- Challenge Institute for Quantum Computation, University of California, Los Angeles, California 90095, United States
| | - Anastassia N Alexandrova
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
| | - Eric R Hudson
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
- Challenge Institute for Quantum Computation, University of California, Los Angeles, California 90095, United States
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Holland CM, Lu Y, Cheuk LW. Bichromatic Imaging of Single Molecules in an Optical Tweezer Array. PHYSICAL REVIEW LETTERS 2023; 131:053202. [PMID: 37595242 DOI: 10.1103/physrevlett.131.053202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 07/04/2023] [Indexed: 08/20/2023]
Abstract
We report on a novel bichromatic fluorescent imaging scheme for background-free detection of single CaF molecules trapped in an optical tweezer array. By collecting fluorescence on one optical transition while using another for laser cooling, we achieve an imaging fidelity of 97.7(2)% and a nondestructive detection fidelity of 95.5(6)%. Notably, these fidelities are achieved with a modest photon budget, suggesting that the method could be extended to more complex laser-coolable molecules with less favorable optical cycling properties. We also report on a framework and new methods to characterize various loss mechanisms that occur generally during fluorescent detection of trapped molecules, including two-photon decay and admixtures of higher excited states that are induced by the trapping light. In particular, we develop a novel method to dispersively measure transition matrix elements between electronically excited states. The method could also be used to measure arbitrarily small Franck-Condon factors between electronically excited states, which could significantly aid in ongoing efforts to laser cool complex polyatomic molecules.
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Affiliation(s)
- Connor M Holland
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Yukai Lu
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Lawrence W Cheuk
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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Zhang C, Hutzler NR, Cheng L. Intensity-Borrowing Mechanisms Pertinent to Laser Cooling of Linear Polyatomic Molecules. J Chem Theory Comput 2023. [PMID: 37384588 DOI: 10.1021/acs.jctc.3c00408] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
A study of the intensity-borrowing mechanisms important to optical cycling transitions in laser-coolable polyatomic molecules arising from non-adiabatic coupling, contributions beyond the Franck-Condon approximation, and Fermi resonances is reported. It has been shown to be necessary to include non-adiabatic coupling to obtain computational accuracy that is sufficient to be useful for laser cooling of molecules. The predicted vibronic branching ratios using perturbation theory based on the non-adiabatic mechanisms have been demonstrated to agree well with those obtained from variational discrete variable representation calculations for representative molecules including CaOH, SrOH, and YbOH. The electron-correlation and basis-set effects on the calculated transition properties, including the vibronic coupling constants, the spin-orbit coupling matrix elements, and the transition dipole moments, and on the calculated branching ratios have been thoroughly studied. The vibronic branching ratios predicted using the present methodologies demonstrate that RaOH is a promising radioactive molecule candidate for laser cooling.
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Affiliation(s)
- Chaoqun Zhang
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Nicholas R Hutzler
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California 91125, United States
| | - Lan Cheng
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
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Sinenka H, Bruyakin Y, Zaitsevskii A, Isaev T, Bochenkova AV. Zwitterions Functionalized by Optical Cycling Centers: Toward Laser-Coolable Polyatomic Molecular Cations. J Phys Chem Lett 2023:5784-5790. [PMID: 37327400 DOI: 10.1021/acs.jpclett.3c00904] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Functionalization of large aromatic compounds and biomolecules with optical cycling centers (OCC) is of considerable interest for the design and engineering of molecules with a highly selective optical photoresponse. Both internal and external dynamics in such molecules can be precisely controlled by lasers, enabling their efficient cooling and opening up broad prospects for high-precision spectroscopy, ultracold chemistry, enantiomer separation, and various other fields. The way the OCC is bonded to a molecular ligand is crucial to the optical properties of the OCC, first of all, for the degree of closure of the optical cycling loop. Here we introduce a novel type of functionalized molecular cation where a positively charged OCC is bonded to various organic zwitterions with a particularly high permanent dipole moment. We consider strontium(I) complexes with betaine and other zwitterionic ligands and show the possibility of creating efficient and highly closed population cycling for dipole-allowed optical transitions in such complexes.
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Affiliation(s)
- Hryhory Sinenka
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Yurii Bruyakin
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Andrei Zaitsevskii
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- NRC "Kurchatov Institute" - PNPI, Orlova Roscha, 1, 188300 Gatchina, Russia
| | - Timur Isaev
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
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