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Optical Monitoring of the Magnetization Switching of Single Synthetic-Antiferromagnetic Nanoplatelets with Perpendicular Magnetic Anisotropy. ACS PHOTONICS 2023; 10:1512-1518. [PMID: 37215319 PMCID: PMC10197163 DOI: 10.1021/acsphotonics.3c00123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Indexed: 05/24/2023]
Abstract
Synthetic antiferromagnetic nanoplatelets (NPs) with a large perpendicular magnetic anisotropy (SAF-PMA NPs) have a large potential in future local mechanical torque-transfer applications for e.g., biomedicine. However, the mechanisms of magnetization switching of these structures at the nanoscale are not well understood. Here, we have used a simple and relatively fast single-particle optical technique that goes beyond the diffraction limit to measure photothermal magnetic circular dichroism (PT MCD). This allows us to study the magnetization switching as a function of applied magnetic field of single 122 nm diameter SAF-PMA NPs with a thickness of 15 nm. We extract and discuss the differences between the switching field distributions of large ensembles of NPs and of single NPs. In particular, single-particle PT MCD allows us to address the spatial and temporal heterogeneity of the magnetic switching fields of the NPs at the single-particle level. We expect this new insight to help understand better the dynamic torque transfer, e.g., in biomedical and microfluidic applications.
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Single organic molecules for photonic quantum technologies. NATURE MATERIALS 2021; 20:1615-1628. [PMID: 33972762 DOI: 10.1038/s41563-021-00987-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 03/17/2021] [Indexed: 05/24/2023]
Abstract
Isolating single molecules in the solid state has allowed fundamental experiments in basic and applied sciences. When cooled down to liquid helium temperature, certain molecules show transition lines that are tens of megahertz wide, limited by only the excited-state lifetime. The extreme flexibility in the synthesis of organic materials provides, at low costs, a wide palette of emission wavelengths and supporting matrices for such single chromophores. In the past few decades, their controlled coupling to photonic structures has led to an optimized interaction efficiency with light. Molecules can hence be operated as single-photon sources and as nonlinear elements with competitive performance in terms of coherence, scalability and compatibility with diverse integrated platforms. Moreover, they can be used as transducers for the optical read-out of fields and material properties, with the promise of single-quanta resolution in the sensing of charges and motion. We show that quantum emitters based on single molecules hold promise to play a key role in the development of quantum science and technologies.
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Giant magnetic susceptibility of gold nanorods detected by magnetic alignment. PHYSICAL REVIEW LETTERS 2013; 111:127202. [PMID: 24093295 DOI: 10.1103/physrevlett.111.127202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Indexed: 06/02/2023]
Abstract
We have determined the magnetic properties of single-crystalline Au nanorods in solution using an optically detected magnetic alignment technique. The rods exhibit a large anisotropy in the magnetic volume susceptibility (Δχ(V)). Δχ(V) increases with decreasing rod size and increasing aspect ratio and corresponds to an average volume susceptibility (χ(V)), which is drastically enhanced relative to bulk Au. This high value of χ(V) is confirmed by SQUID magnetometry and is temperature independent (between 5 and 300 K). Given this peculiar size, shape, and temperature dependence, we speculate that the enhanced χ(V) is the result of orbital magnetism due to mesoscopic electron trajectories within the nanorods.
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Nanoscale probing of charge transport in an organic field-effect transistor at cryogenic temperatures. Phys Chem Chem Phys 2013; 15:4415-21. [DOI: 10.1039/c3cp44072a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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5
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Brownian fluctuations and heating of an optically aligned gold nanorod. PHYSICAL REVIEW LETTERS 2011; 107:037401. [PMID: 21838403 DOI: 10.1103/physrevlett.107.037401] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Indexed: 05/23/2023]
Abstract
We present the first quantitative measurements of the torque exerted on a single gold nanorod in a polarized three-dimensional optical trap. We determined the torque both by observing the time-averaged orientation distribution and by measuring the dynamics of the rotational brownian fluctuations. The measurements are in good agreement with calculations, where the temperature profile around the hot nanorod gives rise to a reduced, effective viscosity. The maximum torque on a 60 nm×25 nm nanorod was 100 pN·nm, large enough to address single-molecule processes in soft and biological matter.
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Toward far-field vibrational spectroscopy of single molecules at room temperature. J Phys Chem B 2011; 115:5425-30. [PMID: 21381637 DOI: 10.1021/jp109652s] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We propose a new scheme for the extraction of chemically sensitive vibrational information from a single fluorescent molecule at room temperature. Our approach is based on a three-photon fluorescence excitation scheme, with selectivity in the production of a vibrational population of the ground state. We estimate the expected signal in perturbation theory for a standard dye molecule, compare its magnitude qualitatively to noise and various background sources, and discuss the experimental realization of this scheme.
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2-methylterrylene in hexadecane: do we see single rotational quantum jumps of methyl groups? J Chem Phys 2008; 128:044508. [PMID: 18247970 DOI: 10.1063/1.2827461] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We performed comparative low temperature (2-30 K) hole-burning and single molecule experiments with 2-methylterrylene with the goal to detect single rotational tunneling jumps of methyl groups. The hole-burned spectrum with its sharply structured side features which are perfectly symmetrically arranged with respect to the central hole supports the assignment to rotational tunneling transitions. However, instead of one, three clearly distinguishable methyl groups show up in the spectrum. Based on molecular mechanics simulations we attribute them to different, nearly degenerate orientations of guest molecules in one specific site of the hexadecane lattice. The frequency distribution of spontaneous jumps of single molecules reflects the features of the hole-burned spectra, although the distribution in the single molecule experiments is significantly broader. The photoinduced frequency transformation of single molecules ("single molecule photobleaching experiments") fits to the features of the hole-burned spectra, except that, surprisingly, no significant number of spectral jumps could be generated in the frequency range where the prominent narrow antiholes are observed in the hole-burned spectra.
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Zero-Field Splitting of The T0 and T1 States of 2-Naphthylphenylcarbene from Hole Burning Studies of Triplet-Triplet Transition. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587259608042741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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11
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Hole-Burning Studies on Triplet-Triplet Fluorescence Excitation Spectrum of 2-Naphthylphenylcarbene. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587259608037885] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
Several recently developed detection techniques opened studies of individual metal nanoparticles (1-100 nm in diameter) in the optical far field. Eliminating averaging over the broad size and shape distributions produced by even the best of current synthesis methods, these studies hold great promise for gaining a deeper insight into many of the properties of metal nanoparticles, notably electronic and vibrational relaxation. All methods are based on detection of a scattered wave emitted either by the particle itself, or by its close environment. Direct absorption and interference techniques rely on the particle's scattering and have similar limits in signal-to-noise ratio. The photothermal method uses a photo-induced change in the refractive index of the environment as an additional step to scatter a wave with a different wavelength. This leads to a considerable improvement in signal-to-background ratio, and thus to a much higher sensitivity. We briefly discuss and compare these various techniques, review the new results they generated so far, and conclude on their great potential for nanoscience and for single-molecule labelling in biological assays and live cells.
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Intermolecular intersystem crossing in single-molecule spectroscopy: Terrylene in anthracene crystal. J Chem Phys 2006; 124:164711. [PMID: 16674161 DOI: 10.1063/1.2184311] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We present a spectroscopic study of terrylene in anthracene crystals at the ensemble and single-molecule levels. In this matrix, single-molecule fluorescence is reduced by three orders of magnitude. Correlation measurements allow us to identify a new relaxation channel, matrix-enhanced intersystem crossing. This process starts with a singlet-to-triplet energy transfer from guest to host, after which the triplet exciton is transferred back to the guest. The intermolecular intersystem crossing is expected whenever the lowest triplet state of the host is located between the lowest singlet S(1) and lowest triplet T(1) excited states of the guest. It must be considered when searching for new host-guest systems for single-molecule spectroscopy.
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High-resolution spectroscopy of organic molecules in solids: from fluorescence line narrowing and hole burning to single molecule spectroscopy. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100142a003] [Citation(s) in RCA: 169] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mean-field theory and numerical calculations of the density of states and the absorption of a diagonally disordered mixed crystal. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/18/29/009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18
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A Hole-Burning Study of the Zero-Field Splitting of the Triplet Ground and Excited States of 2,2-Dinaphthylcarbene in n-Heptane and n-Hexane at 1.7 K. J Phys Chem A 2000. [DOI: 10.1021/jp000453q] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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20
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Are the spectral trails of single molecules consistent with the standard two-level system model of glasses at low temperatures? Chem Phys 1999. [DOI: 10.1016/s0301-0104(99)00140-8] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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21
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22
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Zero-Field Splitting of the Electronic Ground and Lowest Excited Triplet States of 2,2-Dinaphthylcarbene in n-Hexane at 1.7 K. J Phys Chem A 1999. [DOI: 10.1021/jp984581e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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Abstract
Efficient collection and detection of fluorescence coupled with careful minimization of background from impurities and Raman scattering now enable routine optical microscopy and study of single molecules in complex condensed matter environments. This ultimate method for unraveling ensemble averages leads to the observation of new effects and to direct measurements of stochastic fluctuations. Experiments at cryogenic temperatures open new directions in molecular spectroscopy, quantum optics, and solid-state dynamics. Room-temperature investigations apply several techniques (polarization microscopy, single-molecule imaging, emission time dependence, energy transfer, lifetime studies, and the like) to a growing array of biophysical problems where new insight may be gained from direct observations of hidden static and dynamic inhomogeneity.
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Stark Effect on Single Molecules of Dibenzanthanthrene in a Naphthalene Crystal and in a n-Hexadecane Shpol'skii Matrix. J Phys Chem A 1999. [DOI: 10.1021/jp983956t] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Perylene in biphenyl and anthracene crystals: an example of the influence of the host on single-molecule signals. Chem Phys 1998. [DOI: 10.1016/s0301-0104(98)00159-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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26
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Pump–probe spectroscopy and photophysical properties of single di-benzanthanthrene molecules in a naphthalene crystal. J Chem Phys 1997. [DOI: 10.1063/1.474525] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Dibenzoterrylene in Naphthalene: A New Crystalline System for Single Molecule Spectroscopy in the Near Infrared. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp960845q] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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29
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Zero-field splitting of the ground and excited triplet states of 2-naphthylphenylcarbene studied by hole-burning on triplet-triplet fluorescence excitation spectra. Chem Phys Lett 1995. [DOI: 10.1016/0009-2614(95)01046-c] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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31
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Pump-Probe Experiments with a Single Molecule: ac-Stark Effect and Nonlinear Optical Response. PHYSICAL REVIEW LETTERS 1995; 75:1514-1517. [PMID: 10060317 DOI: 10.1103/physrevlett.75.1514] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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32
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Single molecule lines and spectral hole burning of terrylene in different matrices. J Chem Phys 1994. [DOI: 10.1063/1.467968] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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33
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34
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35
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Probing individual two-level systems in a polymer by correlation of single molecule fluorescence. PHYSICAL REVIEW LETTERS 1993; 70:3584-3587. [PMID: 10053911 DOI: 10.1103/physrevlett.70.3584] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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36
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Photon bunching in the fluorescence from single molecules: A probe for intersystem crossing. J Chem Phys 1993. [DOI: 10.1063/1.464249] [Citation(s) in RCA: 192] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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37
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Photon antibunching in the fluorescence of a single dye molecule trapped in a solid. PHYSICAL REVIEW LETTERS 1992; 69:1516-1519. [PMID: 10046242 DOI: 10.1103/physrevlett.69.1516] [Citation(s) in RCA: 237] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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38
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39
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40
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Single pentacene molecules detected by fluorescence excitation in a p-terphenyl crystal. PHYSICAL REVIEW LETTERS 1990; 65:2716-2719. [PMID: 10042674 DOI: 10.1103/physrevlett.65.2716] [Citation(s) in RCA: 546] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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41
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42
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Quantum-mechanical-model calculations of radiative properties of a molecular crystal. II. A transition to coherence in the spontaneous emission from disordered two-dimensional excitons. PHYSICAL REVIEW. B, CONDENSED MATTER 1986; 34:680-685. [PMID: 9939674 DOI: 10.1103/physrevb.34.680] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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43
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Exciton-phonon coupling parameters from Kramers-Kronig analysis of anthracene reflectivity spectra at low temperatures. Chem Phys 1985. [DOI: 10.1016/0301-0104(85)80060-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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44
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45
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Pure electronic, vibronic, and two‐particle surface excitons on the anthracene crystal. II. Experimental study and analysis of the (0,1) region. J Chem Phys 1983. [DOI: 10.1063/1.445272] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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46
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Pure electronic, vibronic, and two‐particle surface excitons on the anthracene crystal. I. General theoretical basis, experimental study, and analysis of the (0,0) region. J Chem Phys 1983. [DOI: 10.1063/1.445088] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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