Nonlinear Optics and Dynamics of Relativistically Transparent Plasmas

Lead Research Organisation: University of Strathclyde
Department Name: Physics

Abstract

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The fundamental properties of optics are well understood at moderate light intensities. However, at the highest intensities capable of being produced using state-of-the-art lasers, many new and useful optical phenomena arise. When a high intensity laser pulse is focused onto a medium it generates a plasma and can drive extreme temperatures and intense electric and magnetic fields. This results in the production of beams of high energy particles and radiation with unique properties, which are opening up new frontiers in science and new applications. The plasma electrons quiver in the intense laser field at velocities close to the speed of light, which changes fundamental properties of the plasma, such as its refractive index. The fact that the particle motion and nonlinear optical properties dynamically evolve in response to inter-action with the laser pulse means that the plasma can act as an active optical element. If harnessed, this would provide researchers with a tool to dynamically control both the properties of ultraintense laser light and the beams of charged particles and radiation produced.

Great progress has been made in controlling the collective response of electrons to intense laser pulses propagating in low density (transparent) plasma, resulting in the production of high energy, ultrashort bunches of electrons in a low divergence beam. The situation is more complex in the case of solid density plasma, used for example for ion acceleration and high harmonic generation. The dense plasma acts as a mirror (a plasma mirror), which reflects a significant portion of the laser beam. At ultrahigh laser intensities, however, the nonlinear motion of the plasma electrons results in relativistic optical phenomena which can render the dense plasma transparent.

Our proposed research focuses on exploring relativistic plasma optics in ultrathin foils. Such targets initially act as a plasma mirror, reflecting laser light, and evolve over the course of the interaction to become relativistically transparent. This transient behaviour offers a promising route to controlling charged particle acceleration in dense plasma. During the opaque phase of the interaction, strong longitudinal electrostatic fields are generated, resulting in forward-directed electron and ion beams, which can be controlled using relativistic optical effects induced as the laser propagates through the target during transparency. We will investigate this approach as a means of dynamically controlling fundamental properties of the transmitted intense laser light and the resulting high energy particles and radiation.

We will use the complementary capabilities of the new 350 TW laser at the Scottish Centre for the Applications of Plasma Accelerators, in which new techniques can be developed and optimised over time, and the Gemini and Vulcan lasers at the Central Laser Facility, which offer higher power and dual beam capability. We will also perform closely coupled simulations using high performance computers. This will allow us to investigate the potential for developing relativistic plasma optics processes for the dynamic control of the spatial, temporal and polarisation properties of ultraintense laser pulses. We will investigate the use of this approach for controlling the properties of beams of high energy particles and radiation produced in the interaction. Together with our international partners at the next-generation extreme light infrastructure laser facilities in the Czech Republic and Romania, we will also investigate the physics of relativistic optics and plasma dynamics at ultrahigh intensities, for which high field processes will modify the underpinning physics.

We will develop a clear understanding of ultrahigh intensity optical processes, their potential use in developing plasma optical and photonic devices and the dynamic control of particle and radiation production in dense plasma.
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Planned Impact

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The research outlined in this proposal is a programme of fundamental science with the potential to deliver significant impact on academia and industry in the short term, and society and the economy in the long term.

Plasma optics have the potential to circumvent many of the limitations of conventional solid state optics. They are, for example, much more compact due to their ability to sustain much higher amplitude electromagnetic fields. Importantly, the ultrafast evolution of their optical characteristics enables intra-pulse tailoring of specific properties of high intensity laser light, which opens up new scientific possibilities. The resulting ability to manipulate the properties of high power laser pulses is vital to the development of compact laser-driven high energy sources of particles and radiation. Our proposed project directly addresses this challenge. Its successful realisation could have a profound impact on the development of laser-driven sources in dense plasma. By extension, the research has strong potential for long term, broad societal impact via application of these sources.

Due to their compact nature and the unique properties of the resulting radiation beams (e.g. ultrashort pulse and low emittance), high power laser plasma sources are an enabling technology which, in due course, are likely to be applied in sectors such as healthcare (e.g. solutions to diagnosis and treatment of cancer), energy (e.g. in fusion research) and security (e.g. X-ray probes for penetrative imaging of hidden materials). In healthcare, for example, in addition to reducing the cost and footprint of particle therapy centres, leading to more widespread availability, a laser-driven approach to particle- and radio-therapy is predicted to offer clinical advantages (e.g. via mixed modality for optimised treatment). The development of this approach could contribute to enhancing patient survival rates and could drive inward investment in the health sector. Applications of laser-plasma-driven radiation beams within industry (e.g. for the detection of defects in manufacturing) could increase the competitiveness of UK manufacturing. Thus, the proposed fundamental laser-plasma physics research, which will contribute significantly to the development of high power laser-driven radiation sources in dense plasma (ions, extreme ultraviolet harmonics, terahertz and gamma-radiation), could have significant long-term societal impact.

In the short term, the project will benefit industry and the wider society via the training of potential employees (PDRAs and PhDs) with state-of-the-art experimental and theoretical/numerical expertise. We also plan to explore the potential for commercial exploitation of the plasma optics techniques and plasma photonic devices resulting from this research.

We will proactively engage with academic and non-academic beneficiaries to maximise the impact of the research. The results will be communicated in a variety of formats to relevant researchers within the laser-plasma and accelerator development communities. The uptake of the new nonlinear photonics techniques and mechanisms for controlling particle motion developed within this project forms part of the critical pathway from this research to economic and societal impact. We will also directly engage with potential end-users of the research, in a variety of ways, including two workshops to communicate the results and capture end-user input to the research programme.

We will engage in increasing the public understanding of science via a variety of public lectures and outreach events, along with web-based and social media dissemination. In particular, we aim to raise awareness of how new developments in physics can produce original approaches to addressing key societal challenges (e.g. in the area of healthcare technologies).
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Publications

10 25 50
 
Description This ongoing research project focuses on the physics of laser-driven relativistically transparent plasmas, exploring the evolution of nonlinear optical properties and the effect this has on the propagation of intense laser light, and the generation and evolution of strong fields and forces that define the properties of beams of accelerated particles. The results are of fundamental importance for relativistic laser-plasma physics and for the development of laser-driven schemes for particle and radiation sources. To date, the project has resulted in 26 publications in leading international peer-reviewed journals and numerous invited presentations at national and international conferences and workshops. Highlights from this research programme include: Experimental demonstration of near-100 MeV protons accelerated by high power laser interaction with an ultrathin foil (Nature Communications). This paper reports on an experimental demonstration of high energy protons via a hybrid laser-driven ion acceleration scheme, including the underpinning physics and scaling to the next generation of high power lasers. It has been cited 65 times in less than two years since publication and is included in the "Top 50 Physics" collection for most read Nature Communications physics articles published in 2018. Another highlight is the first demonstration of pulses of THz radiation with record high energies up to tens of millijoules, produced by picosecond laser pulse irradiating a metal foil (Proceedings of the National Academy of Sciences). The output includes demonstration of the use of cryogenic targets for laser-driven ion acceleration. (Physical Review Letters). A number of papers have been published on various aspects of relativistic plasma optics, including the generation of high order modes of intense light in ultrathin foils undergoing relativistic induced transparency (Sci. Reports). The influence of high field phenomena on the dynamics of thin foils irradiated by intense laser light has also been investigated (Sci. Reports). The project is ongoing at the time of this update (March 2020).
Exploitation Route Too early
Sectors Energy,Healthcare,Security and Diplomacy

 
Title Data for: "An optically multiplexed singleÂ-shot time resolving probe of laserÂ-plasma dynamics" 
Description "This dataset is associated with the article '""An optically multiplexed singleÂ-shot time resolving probe of laserÂ-plasma dynamics"", which reports on the development, testing and implementation of a novel multiframe optical probe for time-resolved measurements of laser-plasma interactions. The raw images recorded by the probe are included in this archive, as is a readme file describing how the background subtraction was performed (in order to reproduce the images shown in the associated article) and also details of how the channel divergence analysis was performed. " 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact
 
Title Data for: "Bremsstrahlung emission profile from intense laser-solid interactions as a function of laser focal spot size" 
Description Experimental data for paper on the effects of defocusing a laser on the spatial profile of the x-ray emission area. A "readme" file is included explaining the specific file formats and software requirements for the included data. Experimental campaign was conducted using the Vulcan laser in Target Area West in May 2017. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact
 
Title Data for: "Bright attosecond ?-ray pulses from nonlinear Compton scattering with laser-illuminated compound targets" 
Description "This data was produced via full three-dimensional particle-in-cell simulations using EPOCH code (version 4.7.6) with the input.deck files included, which corresponds to the results reported in the publication ""Bright attosecond ?-ray pulses from nonlinear Compton scattering with laser-illuminated compound targets"". The files labelled *.deck is the initialization file ('input.deck') used to produce the data, where the * indicates the laser and target parameters. The hardware used to produce the simulation results is listed on the HPCC at Shanghai Jiao Tong University page: https://hpc.sjtu.edu.cn/info/1011/1559.htm Data embargo until 01/05/18" 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact
 
Title Data for: "Control of laser light by a plasma immersed in a tunable strong magnetic field" 
Description The data are about the input files used for numerical simulation with the code Osiris 2.0 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact Too early 
URL https://pureportal.strath.ac.uk/en/datasets/data-for-control-of-laser-light-by-a-plasma-immersed-in-...
 
Title Data for: "Enhanced laser-energy coupling to dense plasmas" 
Description This data corresponds to the experimental and simulation results reported in the publication ""Enhanced laser-energy coupling to dense plasmas ..."". Simulation data was generated by running EPOCH version 4.8.3 with the input.deck files included. Data embargo 19/05/18 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact Unknown 
 
Title Data for: "Escaping electrons from intense laser-solid interactions as a function of laser spot size" 
Description A high powered laser was defocused to observe the effect that this has on the escaping electron population. The data was recorded on Image plate and saved as a .Fit file. Analysis of the diagnostic was conducted using GEANT4 and PIC simulations regarding the self-focusing of the laser on the front surface were also done. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact Too early 
URL https://edata.stfc.ac.uk/handle/edata/731
 
Title Data for: "High order mode structure of intense light fields generated via a laser-driven relativistic plasma aperture" 
Description This data corresponds to the experimental and simulation results reported in the publication "High order mode structure of intense light fields generated via a laser-driven relativistic plasma aperture". Simulation data was generated by running EPOCH version 4.8.3 with the input.deck files included. Experimental data was obtained as described in the publication. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Impact Too early 
URL https://pureportal.strath.ac.uk/en/datasets/data-for-high-order-mode-structure-of-intense-light-fiel...
 
Title Data for: "Multi-millijoule coherent terahertz bursts from picosecond laser-irradiated metal foils" 
Description This dataset includes experimental and numerical data from the manuscript 'Multi-millijoule coherent terahertz bursts from picosecond laser-irradiated metal foils'. The experimental data are obtained in the experiment titled "Intense terahertz radiation from picosecond laser-produced plasmas" (App No.: 16110035, PI: David Neely), performed at TAW Vulcan from 8th May 2017 to 10th June 2017. The data are taken to demonstrate a terahertz (THz) pule energy as high as tens of millijoules (mJ) and identify the underlying THz generation mechanisms. Please see the file named "Data description" in the root directory of the attached zip file for a detailed description of the data contained therein. The acquisition and analysis methods of the data can also be found in the manuscript. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact Too early 
URL https://pureportal.strath.ac.uk/en/datasets/data-for-multi-millijoule-coherent-terahertz-bursts-from...
 
Title Data for: "Near-100 MeV protons via a laser-driven transparency-enhanced hybrid acceleration scheme" 
Description The attached data corresponds to the experimental and simulation results included in the article ""Near-100 MeV protons via a laser-driven transparency-enhanced hybrid acceleration scheme"". The study focused on an investigation of ion acceleration from an ultrathin foil target irradiated by an ultraintense (~3x10^{20} W/cm^{2}) laser pulse. This was investigated experimentally and via 3D particle-in-cell simulations. Simulation data was generated by running EPOCH version 4.3.7 with the input.deck files. Data used in figures 2 to 9 was generated by running EPOCH version 4.3.7 with the input.deck files. The hardware used to generate the results is listed on the STFC Scientific Computing Application Resource for Facilities page: http://www.scarf.rl.ac.uk/hardware 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact Unknown 
 
Title Data for: "Radiation pressure-driven plasma surface dynamics in ultra-intense laser pulse interactions with ultra-thin foils" 
Description "This data was generated via experiment using the Gemini laser at the Rutherford Appleton Laboratory and particle-in-cell simulations using the three-dimensional EPOCH code. For the simulation data: The files labelled *.deck is the initialization file (Â'Input deckÂ') used to generate the data. The * denotes the target thickness. " 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact
 
Title Data for: "Reflection of intense laser light from microstructured targets as a potential diagnostic of laser focus and plasma temperature" 
Description This data corresponds to the experimental, simulation and modelling results reported in the publication "Reflection of intense laser light from microstructured targets as a potential diagnostic of laser focus and plasma temperature". Simulation data was generated using EPOCH version 4.8.3 using the .deck files provided. Modelling was done using MATLAB version R2017B using the MATLAB scripts included. Data embargo until 01/01/19 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact
 
Title Data for: "Relativistic Doppler-boosted gamma-rays in High Fields" 
Description The attached data corresponds to the simulation results included in the article "Relativistic Doppler-boosted gamma-rays in High Fields". The dataset comprises of 9 files of simulation data created using EPOCH version 4.8.3. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact
 
Title Data for: "Role of magnetic field evolution on filamentary structure formation in intense laser-foil interactions" 
Description "This data corresponds to the experimental and simulation results reported in the publication ""Role of magnetic field evolution on filamentary structure formation in intense laser-foil interactions"". Simulation data was generated by running EPOCH version 4.8.3 with the input.deck files included. Experimental data was obtained as described in the publication. Data embargo until 28/02/19" 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact
 
Title Data for: "Simultaneous polarization transformation and amplification of multi-petawatt laser pulses in magnetized plasmas" 
Description The data are about the input files used for numerical simulation with the code Osiris 2.0 (https://picksc.idre.ucla.edu/software/software-production-codes/osiris/) to produce figures 1-6 in the paper, which is published in the Optics Express 27 (14), 19319-19330 (2019). The input files are in the plain text format, which can be opened with various text editors. Data embargo until 01/07/19 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
 
Title Data for: Â"Study of backward terahertz radiation from intense picosecond laser-solid interactions using a multichannel calorimeter systemÂ" 
Description "The data is from a multichannel calorimeter system, which is taken in intense laser-plasma interactions experiments. This work has been illustrated in the paper Â"Study of backward terahertz radiation from intense picosecond laser-solid interactions using a multichannel calorimeter systemÂ". The data is taken to study the backward THz generation mechanism in intense laser-solid interactions using a multichannel calorimeter system. The creation method and description of the data can be find in the manuscript. External deposit with eData: the STFC Research Data Repository" 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact
 
Description GCRF Space Radiation Workshop 
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 GCRF Space Radiation Workshop
Year(s) Of Engagement Activity 2018
 
Description Invited Talk / Lecture at the Culham Plasma Physics Summer School 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Undergraduate students
Results and Impact Invited Talk / Lecture at the Culham Plasma Physics Summer School 2018
Year(s) Of Engagement Activity 2018
 
Description Invited Talk / Tutorial at the 2nd International Conference on Nuclear Photonics 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited Talk / Tutorial at the 2nd International Conference on Nuclear Photonics
Year(s) Of Engagement Activity 2018
 
Description Invited Talk at the 35th European Conference on Laser Interaction with Matter 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited Talk at the 35th European Conference on Laser Interaction with Matter
Year(s) Of Engagement Activity 2018
 
Description Invited Talk at the 3rd International Conference on High Power Laser Science and Engineering 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited Talk at the 3rd International Conference on High Power Laser Science and Engineering
Year(s) Of Engagement Activity 2018
 
Description Invited Talk at the GSI PHELIX 10th Anniversary Workshop on Laser-Plasma Physics 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited Talk at the GSI PHELIX 10th Anniversary Workshop on Laser-Plasma Physics
Year(s) Of Engagement Activity 2018
 
Description Invited Talk at the Institute of Physics Nuclear Physics Conference 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited Talk at the Institute of Physics Nuclear Physics Conference 2018
Year(s) Of Engagement Activity 2018
URL https://www.uws.ac.uk/events/2018/april/institute-of-physics-nuclear-physics-conference/
 
Description Invited Talk at the International Conference on Laser-Optics 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited Talk at the International Conference on Laser-Optics 2018
Year(s) Of Engagement Activity 2018
 
Description Invited seminar at the University of Oxford 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Invited seminar at the University of Oxford
Year(s) Of Engagement Activity 2018