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ter Huurne SET, Peeters DBL, Sánchez-Gil JA, Rivas JG. Direct Measurement of the Local Density of Optical States in the Time Domain. ACS PHOTONICS 2023; 10:2980-2986. [PMID: 37602289 PMCID: PMC10436706 DOI: 10.1021/acsphotonics.3c00781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Indexed: 08/22/2023]
Abstract
One of the most fundamental and relevant properties of a photonic system is the local density of optical states (LDOS) as it defines the rate at which an excited emitter dissipates energy by coupling to its surrounding. However, the direct determination of the LDOS is challenging as it requires measurements of the complex electric field of a point dipole at its own position. We introduce here a near-field setup which can measure the terahertz electric field amplitude at the position of a point source in the time domain. From the measured amplitude, the frequency-dependent imaginary component of the electric field can be determined and the LDOS can be retrieved. As a proof of concept, this setup has been used to measure the partial LDOS (the LDOS for a defined dipole orientation) as a function of the distance to planar interfaces made of gold, InSb, and quartz. Furthermore, the spatially dependent partial LDOS of a resonant gold rod has been measured as well. These results have been compared with analytical results and simulations. The excellent agreement between measurements and theory demonstrates the applicability of this setup for the quantitative determination of the LDOS in complex photonic systems.
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Affiliation(s)
- Stan E. T. ter Huurne
- Department of Applied Physics and Science Education,
and Eindhoven Hendrik Casimir Institute, Eindhoven University of
Technology, P.O. Box 513, Eindhoven 5600 MB, The
Netherlands
| | - Djero B. L. Peeters
- Department of Applied Physics and Science Education,
and Eindhoven Hendrik Casimir Institute, Eindhoven University of
Technology, P.O. Box 513, Eindhoven 5600 MB, The
Netherlands
| | - Jose A. Sánchez-Gil
- Instituto de Estructura de La Materia,
Consejo Superior de Investigaciones Científicas
(IEM-CSIC), Serrano 121, Madrid 28006, Spain
| | - Jaime Gómez Rivas
- Department of Applied Physics and Science Education,
and Eindhoven Hendrik Casimir Institute, Eindhoven University of
Technology, P.O. Box 513, Eindhoven 5600 MB, The
Netherlands
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Stanfield LD, Powell AW, Horsley SAR, Sambles JR, Hibbins AP. Microwave demonstration of Purcell effect enhanced radiation efficiency. Sci Rep 2023; 13:5065. [PMID: 36977812 PMCID: PMC10050203 DOI: 10.1038/s41598-023-32066-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/22/2023] [Indexed: 03/30/2023] Open
Abstract
We experimentally demonstrate a Purcell effect-based design technique for improved impedance matching, and thus enhanced the reflection coefficient from a small microwave emitter. Using an iterative process centred on comparing the phase of the radiated field of the emitter in air with that of the emitter in a dielectric environment, we optimise the structure of a dielectric hemisphere above a ground plane surrounding a small monopolar microwave emitter in order to maximise its radiation efficiency. The optimised system shows very strong coupling between the emitter and two omnidirectional radiation modes at 1.99 GHz and 2.84 GHz, yielding Purcell enhancement factors of 1762 and 411 times increase respectively, and near perfect radiation efficiency.
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Affiliation(s)
- L D Stanfield
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK.
| | - A W Powell
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK
| | - S A R Horsley
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK
| | - J R Sambles
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK
| | - A P Hibbins
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK
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Melnikov A, Maeder M, Friedrich N, Pozhanka Y, Wollmann A, Scheffler M, Oberst S, Powell D, Marburg S. Acoustic metamaterial capsule for reduction of stage machinery noise. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 147:1491. [PMID: 32237831 DOI: 10.1121/10.0000857] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 02/19/2020] [Indexed: 06/11/2023]
Abstract
Noise mitigation of stage machinery can be quite demanding and requires innovative solutions. In this work, an acoustic metamaterial capsule is proposed to reduce the noise emission of several stage machinery drive trains, while still allowing the ventilation required for cooling. The metamaterial capsule consists of c-shape meta-atoms, which have a simple structure that facilitates manufacturing. Two different metamaterial capsules are designed, simulated, manufactured, and experimentally validated that utilize an ultra-sparse and air-permeable reflective meta-grating. Both designs demonstrate transmission loss peaks that effectively suppress gear mesh noise or other narrow band noise sources. The ventilation by natural convection was numerically verified, and was shown to give adequate cooling, whereas a conventional sound capsule would lead to overheating. The noise spectra of three common stage machinery drive trains are numerically modelled, enabling one to design meta-gratings and determine their noise suppression performance. The results fulfill the stringent stage machinery noise limits, highlighting the benefit of using metamaterial capsules of simple c-shape structure.
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Affiliation(s)
- Anton Melnikov
- Chair of Vibroacoustics of Vehicles and Machines, Boltzmannstrasse 15, Technical University of Munich, Garching, Bavaria 85748, Germany
| | - Marcus Maeder
- Chair of Vibroacoustics of Vehicles and Machines, Boltzmannstrasse 15, Technical University of Munich, Garching, Bavaria 85748, Germany
| | - Niklas Friedrich
- SBS Bühnentechnik GmbH, Bosewitzer Strasse 20, Dresden, Saxony 01259, Germany
| | - Yan Pozhanka
- CADFEM-CIS, Kondrat'yevskiy Prospekt 15, Saint Petersburg, Northwestern Federal District 195197, Russia
| | - Alexander Wollmann
- Applied Mechanics Group, University of Applied Sciences, Kornmarkt 1, Zwickau, Saxony 08056, Germany
| | - Michael Scheffler
- Applied Mechanics Group, University of Applied Sciences, Kornmarkt 1, Zwickau, Saxony 08056, Germany
| | - Sebastian Oberst
- Centre for Audio, Acoustics and Vibration University of Technology Sydney, 15 Broadway, Sydney, New South Wales 2007, Australia
| | - David Powell
- School of Engineering and Information Technology, University of New South Wales, Northcott Drive, Canberra, Australian Capital Territory 2612, Australia
| | - Steffen Marburg
- Chair of Vibroacoustics of Vehicles and Machines, Boltzmannstrasse 15, Technical University of Munich, Garching, Bavaria 85748, Germany
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Schmidt MK, Helt LG, Poulton CG, Steel MJ. Elastic Purcell Effect. PHYSICAL REVIEW LETTERS 2018; 121:064301. [PMID: 30141687 DOI: 10.1103/physrevlett.121.064301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Indexed: 06/08/2023]
Abstract
In this work, we introduce an elastic analog of the Purcell effect and show theoretically that spherical nanoparticles can serve as tunable and robust antennas for modifying the emission from localized elastic sources. This effect can be qualitatively described by introducing elastic counterparts of the familiar electromagnetic parameters: local density of elastic states, elastic Purcell factor, and effective volume of elastic modes. To illustrate our framework, we consider the example of a submicron gold sphere as a generic elastic GHz antenna and find that shear and mixed modes of low orders in such systems offer considerable elastic Purcell factors. This formalism opens pathways towards extended control over dissipation of vibrations in various optomechanical systems and contributes to closing the gap between classical and quantum-mechanical treatments of phonons localized in elastic nanoresonators.
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Affiliation(s)
- Mikołaj K Schmidt
- Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS), Australia
- Macquarie University Research Centre in Quantum Science and Technology (QSciTech), MQ Photonics Research Centre, Department of Physics and Astronomy, Macquarie University, New South Wales 2109, Australia
| | - L G Helt
- Department of Physics, Engineering Physics & Astronomy, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Christopher G Poulton
- Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS), Australia
- School of Mathematical and Physical Sciences, University of Technology Sydney, New South Wales 2007, Australia
| | - M J Steel
- Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS), Australia
- Macquarie University Research Centre in Quantum Science and Technology (QSciTech), MQ Photonics Research Centre, Department of Physics and Astronomy, Macquarie University, New South Wales 2109, Australia
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