Acoustoelectric Methods for the Generation Manipulation and Detection of THz Radiation
Lead Research Organisation:
University of Nottingham
Department Name: Sch of Physics & Astronomy
Abstract
The conversion of acoustic signals (sound) to electrical signals, and vice-versa, is a technology that has found widespread practical applications. These include, for example: microphones and loudspeakers for sound recording and reproduction at audio frequencies (approx 20 Hz to 20 kHz); transducers for ultrasonic pulse-echo measurement and ultrasonic imaging systems (approx 20 KHz to 100s of MHz); and surface acoustic wave devices for signal processing in mobile communication devices (100s of MHz to a few GHz). The aim of this project is to develop a new technology for conversion between acoustic and electromagnetic (EM) signals, which works at much higher frequencies (10s of GHz to a few THz) and exploits acoustoelectric and piezojunction effects in semiconductor nanostructures and devices.
Acoustoelectric effects in semiconductors are due to the electrons "riding" the acoustic wave as it travels through the crystal. The electrons are effectively dragged along by the sound wave from one electrical contact to the other, giving rise to an electrical current. We have recently obtained experimental evidence for acoustoelectric effect at acoustic wave frequencies up to 100s of GHz in semiconductor nanostructures which points to the feasibility of the proposed project to reach the THz range. The piezojunction effect is a related phenomenon, where the sound wave modulates the electrical conduction across an interface, or junction, between semiconductors such as found in, for example, diodes and transistors. Again, recent experimental evidence obtained by us shows that the piezojunction effect works to very high (THz) frequencies. In the project we will investigate a number of the most promising devices for acoustoelectric applications, and optimise their sensitivity and speed in response to the THz acoustic waves generated by ultrafast laser techniques or saser (sound laser).
Potential applications, which we will explore in this project, include: new and improved methods of generation, manipulation and detection of THZ EM waves, e.g. heterodyne mixing of THz sound with THz EM waves, which have applications is scientific research, medical imaging and security screening; and the generation and detection of nanometre wavelength hypersound, which may be used to extend the established ultrasonics measurement and imaging techniques to the study of materials and structures at the nanoscale.
Acoustoelectric effects in semiconductors are due to the electrons "riding" the acoustic wave as it travels through the crystal. The electrons are effectively dragged along by the sound wave from one electrical contact to the other, giving rise to an electrical current. We have recently obtained experimental evidence for acoustoelectric effect at acoustic wave frequencies up to 100s of GHz in semiconductor nanostructures which points to the feasibility of the proposed project to reach the THz range. The piezojunction effect is a related phenomenon, where the sound wave modulates the electrical conduction across an interface, or junction, between semiconductors such as found in, for example, diodes and transistors. Again, recent experimental evidence obtained by us shows that the piezojunction effect works to very high (THz) frequencies. In the project we will investigate a number of the most promising devices for acoustoelectric applications, and optimise their sensitivity and speed in response to the THz acoustic waves generated by ultrafast laser techniques or saser (sound laser).
Potential applications, which we will explore in this project, include: new and improved methods of generation, manipulation and detection of THZ EM waves, e.g. heterodyne mixing of THz sound with THz EM waves, which have applications is scientific research, medical imaging and security screening; and the generation and detection of nanometre wavelength hypersound, which may be used to extend the established ultrasonics measurement and imaging techniques to the study of materials and structures at the nanoscale.
Planned Impact
This research programme addresses a new area of science and technology, that of terahertz (THz) acousto-electronics. The research objectives are concerned with reaching a fundamental understanding of THz acousto-electric phenomena in semiconductor nanodevices and, through the integration of THz acoustics with THz electromagnetic technologies, developing a brand new class of electronic devices for high-frequency applications, which is an area identified for growth in the EPSRC "Shaping Capability" exercise. The project will impact on a number of the EPSRC thematic areas including: Information and communication technologies; Engineering; Physical sciences; and Healthcare technologies.
In the medium to long term, the project has the potential for significant economic and societal impact, through the development of new high-frequency devices and techniques. For example, applications of the THz acousto-electronic technologies in Information and Communications technologies include:
(1) single-chip low phase noise THz sources based on conversion of sound laser (saser) acoustic radiation to electromagnetic radiation;
(2) bulk acoustic wave filters working at frequencies up to 100s of GHz. The bandpass filter element in this case would be a superlattice structure sandwiched between the acoustoelectric devices used for conversion between sub-THz electrical and acoustical signals. Such devices could potentially be integrated with the acoustic/THz mixer, which will be developed in this project, and also conventional SAW IF filters to provide a complete sub-THz receiver front end including pre-selection, mixing and bandpass filtering elements on a single device.
Related to these potential applications, we have identified a UK-based international company, e2v, that is directly interested from the outset in the knowledge generated by this project (see letter of support).
In the shorter term, the project will impact on research and spectroscopy: THz acoustics extends ultrasonic measurements to the nanoscale. Applications include the non-destructive probing of optically opaque nanostructures in research and for industrial quality control and to probe biological samples with sub-cellular resolution. Currently THz acoustics requires specialized ultrafast optical setups, but the development of convenient and low-cost acousto-electric devices will enable more widespread application of THz acoustics in research and industry. As THz spectroscopy techniques have become more established, they have found many applications, e.g. in materials and biomedical research. The sensitivity to specific materials which have resonances in the THz range has led to applications in security screening, e.g. identifying explosive materials, and in pharmaceutical research. THz acousto-electric devices described in this proposal could be utilized for the manipulation of THz signals in high-resolution THz spectroscopy systems, for example, a "single-chip" spectrometer using acousto-electric THz generator and mixer both driven by a saser oscillator.
In the medium to long term, the project has the potential for significant economic and societal impact, through the development of new high-frequency devices and techniques. For example, applications of the THz acousto-electronic technologies in Information and Communications technologies include:
(1) single-chip low phase noise THz sources based on conversion of sound laser (saser) acoustic radiation to electromagnetic radiation;
(2) bulk acoustic wave filters working at frequencies up to 100s of GHz. The bandpass filter element in this case would be a superlattice structure sandwiched between the acoustoelectric devices used for conversion between sub-THz electrical and acoustical signals. Such devices could potentially be integrated with the acoustic/THz mixer, which will be developed in this project, and also conventional SAW IF filters to provide a complete sub-THz receiver front end including pre-selection, mixing and bandpass filtering elements on a single device.
Related to these potential applications, we have identified a UK-based international company, e2v, that is directly interested from the outset in the knowledge generated by this project (see letter of support).
In the shorter term, the project will impact on research and spectroscopy: THz acoustics extends ultrasonic measurements to the nanoscale. Applications include the non-destructive probing of optically opaque nanostructures in research and for industrial quality control and to probe biological samples with sub-cellular resolution. Currently THz acoustics requires specialized ultrafast optical setups, but the development of convenient and low-cost acousto-electric devices will enable more widespread application of THz acoustics in research and industry. As THz spectroscopy techniques have become more established, they have found many applications, e.g. in materials and biomedical research. The sensitivity to specific materials which have resonances in the THz range has led to applications in security screening, e.g. identifying explosive materials, and in pharmaceutical research. THz acousto-electric devices described in this proposal could be utilized for the manipulation of THz signals in high-resolution THz spectroscopy systems, for example, a "single-chip" spectrometer using acousto-electric THz generator and mixer both driven by a saser oscillator.
Publications
Poyser CL
(2015)
Coherent phonon optics in a chip with an electrically controlled active device.
in Scientific reports
Heywood SL
(2016)
Heterodyne mixing of millimetre electromagnetic waves and sub-THz sound in a semiconductor device.
in Scientific reports
Beardsley R
(2016)
Corrigendum: Nanomechanical probing of the layer/substrate interface of an exfoliated InSe sheet on sapphire.
in Scientific reports
Mogunov I
(2020)
Photoelasticity of VO 2 nanolayers in insulating and metallic phases studied by picosecond ultrasonics
in Physical Review Materials
Whale J
(2018)
Photoelastic properties of zinc-blende Al x Ga 1 - x N in the UV: Picosecond ultrasonic studies
in Physical Review Materials
Poyser CL
(2017)
Phonon Spectroscopy with Chirped Shear and Compressive Acoustic Pulses.
in Physical review letters
Greener J
(2018)
Coherent acoustic phonons in van der Waals nanolayers and heterostructures
in Physical Review B
Wang F
(2020)
Ultrafast Strain-Induced Charge Transport in Semiconductor Superlattices
in Physical Review Applied
Srikanthreddy D
(2017)
Piezoelectric Response to Coherent Longitudinal and Transverse Acoustic Phonons in a Semiconductor Schottky Diode
in Physical Review Applied
Description | 1. Demonstration of a semiconductor superlattice converting high frequency acoustic waves to electrical signals; 2.Use of a mm-wave Schottky diode to mix sub-terahertz acoustic and electromagnetic signals; 3. Demonstration of the use of a 2D electron gas to convert high frequency sound waves to electrical signals; 4. Generation of chirped shear mode acoustic pulses and detection due to piezoelectric interaction in a Schottky device; 5. demonstration of the modulation by an acoustic wave of the THz emission by a QCL |
Exploitation Route | Development of a compact sub-THz receiver front end. |
Sectors | Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Electronics |
URL | https://physicsworld.com/a/sound-waves-boost-the-modulation-speed-of-quantum-cascade-lasers/ |
Description | Acoustic control of quantum cascade heterostructures: the THz "S-LASER" |
Amount | £509,154 (GBP) |
Funding ID | EP/V004751/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 12/2021 |
End | 05/2024 |
Description | Hypersonic superoscillations: enhancing the resolution of acoustic imaging |
Amount | £341,722 (GBP) |
Funding ID | RPG-2020-291 |
Organisation | The Leverhulme Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 07/2021 |
End | 12/2024 |
Description | On-chip triple hybrid quantum systems: coupling microwaves to magnon-phonon polarons |
Amount | £395,829 (GBP) |
Funding ID | EP/V056557/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 04/2022 |
End | 09/2024 |
Description | Collaboration with Dr B Glavin of the V E Lashkaryov Institute, Kiev, Ukraine |
Organisation | V E Lashkaryov Institute of Semiconductor Physics |
Country | Russian Federation |
Sector | Academic/University |
PI Contribution | Dr Glavin and his team have provided theoretical support for the project. He has contributed to four of the listed published outputs. |
Collaborator Contribution | Theoretical support |
Impact | Joint publications |
Start Year | 2009 |
Description | e2v |
Organisation | e2v Technologies |
Country | United Kingdom |
Sector | Private |
PI Contribution | Development of new microwave technologies |
Collaborator Contribution | Extended loan of equipment and provision of expert advice |
Impact | Conference presentations |
Start Year | 2013 |
Description | Phonons 2015 |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | International conference on Phonon Scattering in Condensed Matter. Exchange of latest developments in phonon physics. Follow-on meeting in Nanjing, China in 2018 |
Year(s) Of Engagement Activity | 2015 |
URL | https://www.nottingham.ac.uk/conference/fac-sci/physics/phonons2015/index.aspx |