1
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Needham LM, Saavedra C, Rasch JK, Sole-Barber D, Schweitzer BS, Fairhall AJ, Vollbrecht CH, Wan S, Podorova Y, Bergsten AJ, Mehlenbacher B, Zhang Z, Tenbrake L, Saimi J, Kneely LC, Kirkwood JS, Pfeifer H, Chapman ER, Goldsmith RH. Label-free detection and profiling of individual solution-phase molecules. Nature 2024; 629:1062-1068. [PMID: 38720082 DOI: 10.1038/s41586-024-07370-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 04/02/2024] [Indexed: 05/21/2024]
Abstract
Most chemistry and biology occurs in solution, in which conformational dynamics and complexation underlie behaviour and function. Single-molecule techniques1 are uniquely suited to resolving molecular diversity and new label-free approaches are reshaping the power of single-molecule measurements. A label-free single-molecule method2-16 capable of revealing details of molecular conformation in solution17,18 would allow a new microscopic perspective of unprecedented detail. Here we use the enhanced light-molecule interactions in high-finesse fibre-based Fabry-Pérot microcavities19-21 to detect individual biomolecules as small as 1.2 kDa, a ten-amino-acid peptide, with signal-to-noise ratios (SNRs) >100, even as the molecules are unlabelled and freely diffusing in solution. Our method delivers 2D intensity and temporal profiles, enabling the distinction of subpopulations in mixed samples. Notably, we observe a linear relationship between passage time and molecular radius, unlocking the potential to gather crucial information about diffusion and solution-phase conformation. Furthermore, mixtures of biomolecule isomers of the same molecular weight and composition but different conformation can also be resolved. Detection is based on the creation of a new molecular velocity filter window and a dynamic thermal priming mechanism that make use of the interplay between optical and thermal dynamics22,23 and Pound-Drever-Hall (PDH) cavity locking24 to reveal molecular motion even while suppressing environmental noise. New in vitro ways of revealing molecular conformation, diversity and dynamics can find broad potential for applications in the life and chemical sciences.
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Affiliation(s)
- Lisa-Maria Needham
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- School of the Biological Sciences, University of Cambridge, Cambridge, UK
| | - Carlos Saavedra
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Julia K Rasch
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Daniel Sole-Barber
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Beau S Schweitzer
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Alex J Fairhall
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Cecilia H Vollbrecht
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Department of Chemistry and Biochemistry, Kalamazoo College, Kalamazoo, MI, USA
| | - Sushu Wan
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Yulia Podorova
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Anders J Bergsten
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | | | - Zhao Zhang
- Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, WI, USA
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA
| | - Lukas Tenbrake
- Institut für Angewandte Physik, Universität Bonn, Bonn, Germany
| | - Jovanna Saimi
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Lucy C Kneely
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Jackson S Kirkwood
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Hannes Pfeifer
- Institut für Angewandte Physik, Universität Bonn, Bonn, Germany
| | - Edwin R Chapman
- Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, WI, USA
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA
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2
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Tenbrake L, Faßbender A, Hofferberth S, Linden S, Pfeifer H. Direct laser-written optomechanical membranes in fiber Fabry-Perot cavities. Nat Commun 2024; 15:209. [PMID: 38172102 PMCID: PMC10764917 DOI: 10.1038/s41467-023-44490-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 12/14/2023] [Indexed: 01/05/2024] Open
Abstract
Integrated micro- and nanophotonic optomechanical experiments enable the manipulation of mechanical resonators on the single phonon level. Interfacing these structures requires elaborate techniques limited in tunability, flexibility, and scaling towards multi-mode systems. Here, we demonstrate a cavity optomechanical experiment using 3D-laser-written polymer membranes inside fiber Fabry-Perot cavities. Vacuum coupling rates of g0/2π ≈ 30 kHz to the fundamental megahertz mechanical mode are reached. We observe optomechanical spring tuning of the mechanical resonator frequency by tens of kilohertz exceeding its linewidth at cryogenic temperatures. The direct fiber coupling, its scaling capabilities to coupled resonator systems, and the potential implementation of dissipation dilution structures and integration of electrodes make it a promising platform for fiber-tip integrated accelerometers, optomechanically tunable multi-mode mechanical systems, and directly fiber-coupled systems for microwave to optics conversion.
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Affiliation(s)
- Lukas Tenbrake
- Institute of Applied Physics, University of Bonn, Bonn, Germany
| | | | | | - Stefan Linden
- Institute of Physics, University of Bonn, Bonn, Germany
| | - Hannes Pfeifer
- Institute of Applied Physics, University of Bonn, Bonn, Germany.
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Gothenburg, Sweden.
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3
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Hughes WJ, Doherty TH, Blackmore JA, Horak P, Goodwin JF. Mode mixing and losses in misaligned microcavities. OPTICS EXPRESS 2023; 31:32619-32636. [PMID: 37859061 DOI: 10.1364/oe.496981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/11/2023] [Indexed: 10/21/2023]
Abstract
We present a study on the optical losses of Fabry-Pérot cavities subject to realistic transverse mirror misalignment. We consider mirrors of the two most prevalent surface forms: idealised spherical depressions, and Gaussian profiles generated by laser ablation. We first describe the mode mixing phenomena seen in the spherical mirror case and compare to the frequently-used clipping model, observing close agreement in the predicted diffraction loss, but with the addition of protective mode mixing at transverse degeneracies. We then discuss the Gaussian mirror case, detailing how the varying surface curvature across the mirror leads to complex variations in round trip loss and mode profile. In light of the severe mode distortion and strongly elevated loss predicted for many cavity lengths and transverse alignments when using Gaussian mirrors, we suggest that the consequences of mirror surface profile are carefully considered when designing cavity experiments.
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Needham LM, Saavedra C, Rasch JK, Sole-Barber D, Schweitzer BS, Fairhall AJ, Vollbrecht CH, Mehlenbacher B, Zhang Z, Tenbrake L, Pfeifer H, Chapman ER, Goldsmith RH. Label-free observation of individual solution phase molecules. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.24.534170. [PMID: 36993572 PMCID: PMC10055403 DOI: 10.1101/2023.03.24.534170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The vast majority of chemistry and biology occurs in solution, and new label-free analytical techniques that can help resolve solution-phase complexity at the single-molecule level can provide new microscopic perspectives of unprecedented detail. Here, we use the increased light-molecule interactions in high-finesse fiber Fabry-Pérot microcavities to detect individual biomolecules as small as 1.2 kDa with signal-to-noise ratios >100, even as the molecules are freely diffusing in solution. Our method delivers 2D intensity and temporal profiles, enabling the distinction of sub-populations in mixed samples. Strikingly, we observe a linear relationship between passage time and molecular radius, unlocking the potential to gather crucial information about diffusion and solution-phase conformation. Furthermore, mixtures of biomolecule isomers of the same molecular weight can also be resolved. Detection is based on a novel molecular velocity filtering and dynamic thermal priming mechanism leveraging both photo-thermal bistability and Pound-Drever-Hall cavity locking. This technology holds broad potential for applications in life and chemical sciences and represents a major advancement in label-free in vitro single-molecule techniques.
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Affiliation(s)
- Lisa-Maria Needham
- Department of Chemistry, University of Wisconsin-Madison, WI, USA
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Carlos Saavedra
- Department of Chemistry, University of Wisconsin-Madison, WI, USA
| | - Julia K. Rasch
- Department of Chemistry, University of Wisconsin-Madison, WI, USA
| | | | | | - Alex J. Fairhall
- Department of Chemistry, University of Wisconsin-Madison, WI, USA
| | | | | | - Zhao Zhang
- Howard Hughes Medical Institute and the Department of Neuroscience, University of Wisconsin-Madison, WI, USA
| | - Lukas Tenbrake
- Institut für Angewandte Physik, Universität Bonn, Wegelerstr. 8, 53115 Bonn, Germany
| | - Hannes Pfeifer
- Institut für Angewandte Physik, Universität Bonn, Wegelerstr. 8, 53115 Bonn, Germany
| | - Edwin R. Chapman
- Howard Hughes Medical Institute and the Department of Neuroscience, University of Wisconsin-Madison, WI, USA
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5
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Doherty TH, Kuhn A, Kassa E. Multi-resonant open-access microcavity arrays for light matter interaction. OPTICS EXPRESS 2023; 31:6342-6355. [PMID: 36823893 DOI: 10.1364/oe.475921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
We report the realisation of a high-finesse open-access cavity array, tailored towards the creation of multiple coherent light-matter interfaces within a compact environment. We describe the key technical developments put in place to fabricate such a system, comprising the creation of tapered pyramidal substrates and an in-house laser machining setup. Cavities made from these mirrors are characterised, by laser spectroscopy, to possess similar optical properties to state-of-the-art fibre-tip cavities, but offer a compelling route towards improved performance, even when used to support only a single mode. The implementation of a 2×2 cavity array and the independent frequency tuning between three neighbouring sites are demonstrated.
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Shen ZM, Zhou XL, Huang DY, Pan YH, Li L, Wang J, Li CF, Guo GC. Continuously and widely tunable frequency-stabilized laser based on an optical frequency comb. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:023001. [PMID: 36858996 DOI: 10.1063/5.0120119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 01/08/2023] [Indexed: 06/18/2023]
Abstract
Continuously and widely tunable lasers, actively stabilized on a frequency reference, are broadly employed in atomic, molecular, and optical (AMO) physics. The frequency-stabilized optical frequency comb (OFC) provides a novel optical frequency reference, with a broadband spectrum that meets the requirement of laser frequency stabilization. Therefore, we demonstrate a frequency-stabilized and precisely tunable laser system based on it. In this scheme, the laser frequency locked to the OFC is driven to jump over the ambiguity zones, which blocks the wide tuning of the locked laser, and tuned until the mode hopping happens with the always-activated feedback loop. Meanwhile, we compensate the gap of the frequency jump with a synchronized acoustic optical modulator to ensure the continuity. This scheme is applied to an external cavity diode laser (ECDL), and we achieve tuning at a rate of about 7 GHz/s, with some readily available commercial electronics. Furthermore, we tune the frequency-stabilized laser only with the feedback of diode current, and its average tuning speed can exceed 100 GHz/s. Due to the resource-efficient configuration and the simplicity of completion, this scheme can be referenced and can find wide applications in AMO experiments.
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Affiliation(s)
- Ze-Min Shen
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
| | - Xiao-Long Zhou
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
| | - Dong-Yu Huang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
| | - Yu-Hao Pan
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
| | - Li Li
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
| | - Jian Wang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
| | - Chuan-Feng Li
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
| | - Guang-Can Guo
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
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7
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Pan Y, Li L, Zhou X, Huang D, Shen Z, Wang J, Li C, Guo G. Feedback and compensation scheme to suppress the thermal effects from a dipole trap beam for the optical fiber microcavity. OPTICS EXPRESS 2022; 30:46280-46293. [PMID: 36558585 DOI: 10.1364/oe.472022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
Cavity quantum electrodynamics (cavity QED) with neutral atoms is a promising platform for quantum information processing and optical fiber Fabry-Pérot microcavity with small mode volume is an important integrant for the large light-matter coupling strength. To transport cold atoms to the microcavity, a high-power optical dipole trap (ODT) beam perpendicular to the cavity axis is commonly used. However, the overlap between the ODT beam and the cavity mirrors causes thermal effects inducing a large cavity shift at the locking wavelength and a differential cavity shift at the probe wavelength which disturbs the cavity resonance. Here, we develop a feedback and compensation scheme to maintain the optical fiber microcavity resonant with the lasers at the locking and probe wavelengths simultaneously. The large cavity shift of 210 times the cavity linewidth, which makes the conventional PID scheme ineffective can be suppressed actively by a PIID feedback scheme with an additional I parameter. Differential cavity shift at the probe wavelength can be understood from the photothermal refraction and thermal expansion effects on the mirror coatings and be passively compensated by changing the frequency of the locking laser. A further normal-mode splitting measurement demonstrates the strong coupling between 85Rb atoms and cavity mode after the thermal effects are suppressed, which also confirms successful delivery and trapping of atoms into the optical cavity. This scheme can solve the thermal effects of the high-power ODT beam and will be helpful to cavity QED experimental research.
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Ruelle T, Jaeger D, Fogliano F, Braakman F, Poggio M. A tunable fiber Fabry-Perot cavity for hybrid optomechanics stabilized at 4 K. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:095003. [PMID: 36182449 DOI: 10.1063/5.0098140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We describe an apparatus for the implementation of hybrid optomechanical systems at 4 K. The platform is based on a high-finesse, micrometer-scale fiber Fabry-Perot cavity, which can be widely tuned using piezoelectric positioners. A mechanical resonator can be positioned within the cavity in the object-in-the-middle configuration by a second set of positioners. A high level of stability is achieved without sacrificing either performance or tunability, through the combination of a stiff mechanical design, passive vibration isolation, and an active Pound-Drever-Hall feedback lock incorporating a reconfigurable digital filter. The stability of the cavity length is demonstrated to be better than a few picometers over many hours both at room temperature and at 4 K.
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Affiliation(s)
- Thibaud Ruelle
- Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - David Jaeger
- Department of Physics, University of Basel, 4056 Basel, Switzerland
| | | | - Floris Braakman
- Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - Martino Poggio
- Department of Physics, University of Basel, 4056 Basel, Switzerland
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