Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

New Journal of Physics

Controlling molecular broadband-emission by optical confinement

Mathias Bernhard Steiner, Antonio Virgilio Failla, Achim Hartschuh, Frank E. Schleifenbaum, Clemens Stupperich, Alfred Johann Meixner

Published Dec 16, 2008• 21 citations
Publisher

Abstract

We investigate experimentally and theoretically the fluorescence emitted by molecular ensembles as well as spatially isolated, single molecules of an organic dye immobilized in a quasi-planar optical microresonator at room temperature. The optically excited dipole emitters couple simultaneously to on- and off-axis cavity resonances of the microresonator. The multi-spectral radiative contributions are strongly modified with respect to free (non-confined) space due to enhancement and inhibition of the molecular spontaneous emission (SpE) rate. By varying the mirror spacing of the microresonator on the nanometer-scale, the SpE rate of the cavity-confined molecules and, consequently, the spectral line width of the microresonator-controlled broadband fluorescence can be tuned by up to one order of magnitude. Stepwise reducing the optical confinement, we observe that the microresonator-controlled molecular fluorescence line shape converges towards the measured fluorescence line shape in free space. Our results are important for research on and application of broadband emitters in nano-optics and -photonics as well as microcavity-enhanced (single molecule) spectroscopy.

DOI
10.1088/1367-2630/10/12/123017

Related papers

Control of molecular Spontaneous Emission in an optical lambda/2-microresonator

Mathias Bernhard Steiner

Control of molecular Spontaneous Emission in an optical λ/2-microresonator\n \nIn this thesis, the influence of a planar optical λ/2-microresonator on the Spontaneous Emission rate of embedded molecules and the implications on the microresonator-controlled emission is investigated by means of scanning confocal optical microscopy and spectroscopy. The experimental results obtained for molecular ensembles as well as for single molecules are compared with calculations and computer simulations based on existing theoretical models.

•Nov 9, 2006•2 citations

Controlling the optical properties of single molecules by optical confinement in a tunable microcavity

Raphael Gutbrod, Alexey I. Chizhik, Anna M. Chizhik +4 more

Optical microcavities are structures which confine light to a small region in the range of one wavelength. The radiation of a quantum emitter is coupled to cavity resonances which leads to an optical confinement of the broadband fluorescence. A practical design for this single-mode microcavity is formed by two silver mirrors enclosing a transparent dielectric medium with single quantum emitters. Steiner et al. have shown that the fluorescence spectra and decay lifetimes of single molecules in this Fabry-Perot type microcavity are strongly dependent on the resonator length.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 1, 2009•1 citation

Highly efficient, tunable single photon source based on single molecules

Mathias Bernhard Steiner, Achim Hartschuh, Rafal A. Korlacki +1 more

The authors studied spatially isolated terrylene molecules immobilized in a quasiplanar optical λ∕2-microresonator using confocal microscopy and spectroscopy at variable temperatures. At T=1.8K, they observed individual molecules relaxing into microresonator-allowed vibronic levels of their electronic ground state by emission of single fluorescence photons. Coupling the purely electronic transition of embedded molecules to the longitudinal photonic mode of the microresonator resulted in an ultimate spectral narrowing and an increased collection efficiency of the emitted single photon wave trains.

Applied Physics Letters•Apr 30, 2007•35 citations

Detection of Single Molecules in Microcavities

N. Lermer, Michael D. Barnes, C-Y. Kung +2 more

A significant limitation in the detection and spectroscopy of individual dye molecules in liquid room temperature samples is the loss of fluorescence signal through chromophore photobleaching. Although often considered a fundamental restriction on sensitivity, it has been shown that the probability per excitation cycle of photobleaching may be reduced by enhancing the spontaneous emission rate of the chromophore located inside a microdroplet, which acts as a optical cavity. Studies of glycerol microdroplets containing R6G dye molecules, and levitated in a three-dimensional electrodynamic trap, have demonstrated a significant enhancement of both the fluorescence decay rate [1] and the total fluorescence yield [2] of the chromophore. Modification of the emission rate is greatest for molecules located near the surface of small (< 10 μm) microdroplets, where the influence of the droplet cavity modes of the droplet is most significant. To exploit this surface sensitivity, surfactant forms of rhodamine dyes were recently studied [3]. Fluorescence emission of the dye molecules, constrained to the droplet surface and with fixed transition moments perpendicular to the surface normal, were shown to be significantly enhanced at small droplet sizes. Additionally, at larger droplet sizes corresponding to higher droplet Q’s, preferential emission into the cavity modes was observed, however the detection of fluorescence photons was delayed by the storage time of the cavity, which may be on the same order as the fluorescence lifetime. These measurements, performed on relatively concentrated dye solutions, suggest that microcavity effects may be exploited to greatly enhance single molecule detection sensitivity in glycerol microdroplets. Furthermore, the large cavity storage time of the high-Q droplets opens the possibility for re-excitation of the molecule following emission into the droplet resonance, and subsequent stimulated emission, that is, single-molecule lasing.

Laser Applications to Chemical, Security and Environmental Analysis•Jan 1, 1998•0 citations

Microcavity‐Controlled Single‐Molecule Fluorescence

Mathias Bernhard Steiner, Frank E. Schleifenbaum, Clemens Stupperich +3 more

We present for the first time cavity-controlled fluorescence spectra and decay curves of single dipole emitters interacting at room temperature with the first longitudinal mode of a Fabry-Perot microcavity offering a lambda/2-spacing between its silver mirrors. The spontaneous emission rate of individual dye molecules was found to be enhanced by the Purcell effect by up to three times compared to the rate in free space, in agreement with theoretical predictions. Moreover, our new microcavity design was found to provide long-term stability and single-molecule sensitivity under ambient conditions for several months without noticeable reduction of the cavity-Q value. We consider this as a significant advance for single-photon sources operating at room temperature.

ChemPhysChem•Sep 22, 2005•60 citations

Coherent coupling of a single molecule to a scanning Fabry-Pérot microcavity

Daqing Wang, Hrishikesh Kelkar, Diego Martín-Cano +3 more

Summary form only given. Organic dye molecules have been used in great many scientific and technological applications. Among these, the polycyclic aromatic hydrocarbons (PAH) behave very favourably as quantum emitters when embedded in organic crystals at temperatures below 4K. PAHs can serve as solid-state emitters with remarkable optical properties such as near-unity quantum efficiency and high photostability. However, transitions to short-lived molecular vibrational levels reduce the scattering cross section by a branching ratio of about 30-50%. In order to overcome this shortcoming and render the molecule as a two-level system, one can enhance its zero-phonon emission by using the Purcell effect, e.g., via coupling to an optical cavity, to obtain a near-unity branching ratio. Here we report the first coherent coupling of a single molecule to a scannable, tunable and broadband microcavity. The cavity consists of a planar distributed Bragg reflector and a micromirror with a radius of curvature of 5 μm fabricated with focused ion-beam milling [1] and coated with silver. By integrating an organic matrix in the microcavity, we are able to coherently couple individual molecules to the cavity mode at liquid helium temperature.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 1, 2017•14 citations
We investigate experimentally and theoretically the fluorescence emitted by molecular ensembles as well as spatially isolated, single molecules of an organic dye immobilized in a quasi-planar optical microresonator at room temperature. The optically excited dipole emitters couple simultaneously to on- and off-axis cavity resonances of the microresonator. The multi-spectral radiative contributions are strongly modified with respect to free (non-confined) space due to enhancement and inhibition of the molecular spontaneous emission (SpE) rate. By varying the mirror spacing of the microresonator on the nanometer-scale, the SpE rate of the cavity-confined molecules and, consequently, the spectral line width of the microresonator-controlled broadband fluorescence can be tuned by up to one order of magnitude. Stepwise reducing the optical confinement, we observe that the microresonator-controlled molecular fluorescence line shape converges towards the measured fluorescence line shape in free space. Our results are important for research on and application of broadband emitters in nano-optics and -photonics as well as microcavity-enhanced (single molecule) spectroscopy.
Control of molecular Spontaneous Emission in an optical λ/2-microresonator\n \nIn this thesis, the influence of a planar optical λ/2-microresonator on the Spontaneous Emission rate of embedded molecules and the implications on the microresonator-controlled emission is investigated by means of scanning confocal optical microscopy and spectroscopy. The experimental results obtained for molecular ensembles as well as for single molecules are compared with calculations and computer simulations based on existing theoretical models.
Optical microcavities are structures which confine light to a small region in the range of one wavelength. The radiation of a quantum emitter is coupled to cavity resonances which leads to an optical confinement of the broadband fluorescence. A practical design for this single-mode microcavity is formed by two silver mirrors enclosing a transparent dielectric medium with single quantum emitters. Steiner et al. have shown that the fluorescence spectra and decay lifetimes of single molecules in this Fabry-Perot type microcavity are strongly dependent on the resonator length.
The authors studied spatially isolated terrylene molecules immobilized in a quasiplanar optical λ∕2-microresonator using confocal microscopy and spectroscopy at variable temperatures. At T=1.8K, they observed individual molecules relaxing into microresonator-allowed vibronic levels of their electronic ground state by emission of single fluorescence photons. Coupling the purely electronic transition of embedded molecules to the longitudinal photonic mode of the microresonator resulted in an ultimate spectral narrowing and an increased collection efficiency of the emitted single photon wave trains.
A significant limitation in the detection and spectroscopy of individual dye molecules in liquid room temperature samples is the loss of fluorescence signal through chromophore photobleaching. Although often considered a fundamental restriction on sensitivity, it has been shown that the probability per excitation cycle of photobleaching may be reduced by enhancing the spontaneous emission rate of the chromophore located inside a microdroplet, which acts as a optical cavity. Studies of glycerol microdroplets containing R6G dye molecules, and levitated in a three-dimensional electrodynamic trap, have demonstrated a significant enhancement of both the fluorescence decay rate [1] and the total fluorescence yield [2] of the chromophore. Modification of the emission rate is greatest for molecules located near the surface of small (< 10 μm) microdroplets, where the influence of the droplet cavity modes of the droplet is most significant. To exploit this surface sensitivity, surfactant forms of rhodamine dyes were recently studied [3]. Fluorescence emission of the dye molecules, constrained to the droplet surface and with fixed transition moments perpendicular to the surface normal, were shown to be significantly enhanced at small droplet sizes. Additionally, at larger droplet sizes corresponding to higher droplet Q’s, preferential emission into the cavity modes was observed, however the detection of fluorescence photons was delayed by the storage time of the cavity, which may be on the same order as the fluorescence lifetime. These measurements, performed on relatively concentrated dye solutions, suggest that microcavity effects may be exploited to greatly enhance single molecule detection sensitivity in glycerol microdroplets. Furthermore, the large cavity storage time of the high-Q droplets opens the possibility for re-excitation of the molecule following emission into the droplet resonance, and subsequent stimulated emission, that is, single-molecule lasing.
We present for the first time cavity-controlled fluorescence spectra and decay curves of single dipole emitters interacting at room temperature with the first longitudinal mode of a Fabry-Perot microcavity offering a lambda/2-spacing between its silver mirrors. The spontaneous emission rate of individual dye molecules was found to be enhanced by the Purcell effect by up to three times compared to the rate in free space, in agreement with theoretical predictions. Moreover, our new microcavity design was found to provide long-term stability and single-molecule sensitivity under ambient conditions for several months without noticeable reduction of the cavity-Q value. We consider this as a significant advance for single-photon sources operating at room temperature.
Summary form only given. Organic dye molecules have been used in great many scientific and technological applications. Among these, the polycyclic aromatic hydrocarbons (PAH) behave very favourably as quantum emitters when embedded in organic crystals at temperatures below 4K. PAHs can serve as solid-state emitters with remarkable optical properties such as near-unity quantum efficiency and high photostability. However, transitions to short-lived molecular vibrational levels reduce the scattering cross section by a branching ratio of about 30-50%. In order to overcome this shortcoming and render the molecule as a two-level system, one can enhance its zero-phonon emission by using the Purcell effect, e.g., via coupling to an optical cavity, to obtain a near-unity branching ratio. Here we report the first coherent coupling of a single molecule to a scannable, tunable and broadband microcavity. The cavity consists of a planar distributed Bragg reflector and a micromirror with a radius of curvature of 5 μm fabricated with focused ion-beam milling [1] and coated with silver. By integrating an organic matrix in the microcavity, we are able to coherently couple individual molecules to the cavity mode at liquid helium temperature.