Focusing Plasma Optics: Towards Extreme Laser Intensities

Lead Research Organisation: University of Strathclyde
Department Name: Physics

Abstract

The use of optics to focus light dates back to the ancient Egyptians and has been instrumental over the centuries in contributing to many scientific discoveries and innovations. In recent years the use of optics to focus laser beams has resulted in countless applications, not only in science, but in information technology, medicine, industry, consumer electronics, entertainment and defence. As ever higher focused laser intensities have been achieved, intense laser light has played a revolutionary role, first in atomic and molecular physics and then plasma physics. At the highest intensities achievable today, focused laser light is opening up new frontiers in science via the production of extreme pressures, temperatures and intense electric and magnetic fields, including driving sources of high energy particles and radiation with unique properties.

The conventional approach to focusing light, based on the use of solid state optical media, has not fundamentally changed over the centuries, but is rapidly becoming a key limiting factor for the further development of ultra-intense laser science. The main reason for this is that there is a limit to the energy density which solid state optical media can withstand before it is damaged. The traditional way to circumvent this is to increase the size of the focusing optic as the laser energy is increased, so that the overall energy density is below the critical value. However, the optics used on the highest power lasers (such as the Vulcan petawatt laser at the UK's Central Laser Facility) are now more than a meter in diameter and are very expensive, with long manufacture times and limited manoeuvrability due to their volume and weight. Radical new approaches are required to enable the maximum achievable laser intensity to continue to be increased and for the production of compact high intensity laser drivers for application.

This proposal aims to explore the feasibility of developing and applying new types of focusing optical systems based on ultrafast plasma processes - focusing plasma optics - to extend the intensity frontier achievable with high power laser pulses. Due to their ability to sustain extremely large amplitude electromagnetic fields, plasma optical components are inherently compact. Energy densities of more than a factor of a hundred higher than conventional solid state optics are easily achievable, which means that plasma optics are more than a factor of ten smaller. Furthermore, the ultrafast evolution of the optical properties of laser-excited plasma enables other properties of the laser pulse to be tailored. For these reasons plasma optical components are likely to become essential elements of future high power laser facilities.

The proposed work involves exploring two avenues for achieving plasma focusing - focusing due to reflection from a curved plasma surface and self-induced focusing due to non-linear plasma effects in transparent plasma. Innovative approaches to controlling the properties of the focal spot achieved are introduced. This will enable approximately a factor of 10 to 20 increase in the maximum intensities achievable at present, opening up the exploration of matter under extremely high temperature and pressure conditions. It will also underpin the development of compact laser-driven high energy particle and radiation sources towards application. Thus the focusing plasma optics to be investigated in this project have truly revolutionary potential as next generation optical devices.

Planned Impact

The ability to manipulate the properties of high power laser pulses and to focus them to achieve ultrahigh intensities is vital to the development of compact laser-driven high energy sources of particles and radiation and their potential real-world applications in medicine, industry and security. Plasma-based optics have the potential to circumvent many of the limitations of conventional solid state optics. Due to their ability to sustain much higher amplitude electromagnetic fields, they are much more compact (more than a factor of ten reduction in the optic size) and importantly the ultrafast evolution of their optical properties also enables tailoring of other properties of the laser pulse. The practical and potential commercial (in terms of application in future compact laser-driven sources) benefits of realising focusing plasma-optics justifies urgent investment in the research and development of such devices.

Due to both the fundamental nature of the research into ultrafast plasma processes and the resulting development to produce focusing plasma optics capable of increasing the maximum optical intensities achievable, the first beneficiaries of the proposed research project will be those in the laser-plasma and related academic communities. Ultimately, however, the higher laser intensities achievable and resulting greater degree of control on laser pulse properties will contribute to the development of new compact laser-driven particle and radiation sources and could lead to greater flexibility in advanced target designs for new energy sources based on inertial fusion, both of which would have wide-ranging benefits to the general public. The potential long-term applications of laser-driven particle beams include, for example, oncology for the treatment of cancer tumours. The development of fusion as an energy source is a long-standing science and engineering Grand Challenge, which would have major impact on energy security. Thus, the underpinning capability developed in this grant to manipulate laser pulse properties with small, disposable plasma optics may, in the long term, benefit society via applications of laser-driven particle and radiation sources in the health and energy sectors.

These possible applications illustrate that focusing plasma optics could have a transformative effect, not only on fundamental ultraintense laser-driven science, but in societal applications of the resulting particle and radiation sources. In fact, the proposed development of a robust and compact plasma-optic platform for manipulating the laser pulse focus will likely help to build momentum and stimulate further research towards realising compact laser-driven sources and their real-world applications. There will be considerable benefit to the UK of leading the development of such an enabling new technology.

Publications

10 25 50

publication icon
King M (2016) Ion acceleration and plasma jet formation in ultra-thin foils undergoing expansion and relativistic transparency in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

publication icon
King M (2017) Energy exchange via multi-species streaming in laser-driven ion acceleration in Plasma Physics and Controlled Fusion

publication icon
MacLellan D (2014) Influence of laser-drive parameters on annular fast electron transport in silicon in Plasma Physics and Controlled Fusion

 
Description This research project focused on investigating the potential for plasma focusing techniques to significantly enhance the peak laser intensities achievable with high power lasers and to explore ways to control the laser focal spot intensity distribution. Two main approaches were investigated, based on (1) optical reflection from a curved plasma surface on a solid, and (2) self-focusing in transparent plasma produced by thin foils expanding. The project has, to date, resulted in 17 research publications in leading peer-review journals. It has also resulted in numerous invited talks at international conference and workshops. A key objective of our programme was the development and optimisation of a compact ellipsoidal plasma mirror for fast focusing, to produce a significant increase in the achievable peak laser intensity for a given set of high power laser pulse parameters. This was fully achieved. A new optic was design, developed, optimised and tested. This was then applied in test shots using the Vulcan Petawatt laser at the Central Laser Facility. A factor of 3.6 enhancement in the laser intensity was achieved, pushing the peak intensity to beyond 10^21 Wcm^-2. The optic was then applied in a first demonstration experiment, which resulted in a factor of 2 increase in the maximum energy of laser-accelerated protons. This highly successful result, which was published in March 2016, led to two successful applications for full experiments using Vulcan-petawatt. These experiments took place in October 2016 and November 2018. The first involved a detailed investigation on the role of tight focusing, using the focusing plasma optics, on laser-driven ion acceleration. The results have been analysed and are being written up for publications. The second experiment focused on the high energy photon generation at ultrahigh laser intensities and the results are being analysed. The project has also led to an invitation to collaborate with researchers at the ELI-Beamlines facility in the Czech Republic to develop similar optics for use there and to trial the optics in an experiment at the Titan laser facility at Lawrence Livermore National Facility in the USA. Another highlight of our research programme was the first demonstration that diffraction of ultra-intense laser light passing through a normally opaque plasma can be used to control charged particle motion. Depending on the degree of plasma expansion of an initial foil target, the incident laser light either self-focuses in the plasma or generates an instantaneous 'relativistic plasma aperture' in the region of the peak laser intensity, leading to diffraction. The results have potentially important implications in the development of laser-driven particle accelerators and radiation sources (which rely on controlling the motion of plasma electrons displaced by the intense laser fields) and for the investigation of aspects of laboratory astrophysics.
Exploitation Route The findings of this research are being put to use by academics working in the field of intense laser-plasma physics. The results have, for example, influenced decisions taken by the UK-wide A-SAIL (Advanced Strategies for the Acceleration of Ions using Lasers) consortium on the development of laser-driven ion sources. The focusing plasma optics developed in this project are influencing the development of the fast focusing programme of the European-scale ELI-Beamlines high power laser facility and are under consideration for use at ELI-Nuclear Physics. As a direct result of our findings in this research project, UK researchers have been invited to join a new consortium on the development of plasma optics for use at the ELI-Beamlines facility. They have also been invited to join an international collaboration experiment at the Titan laser facility at Lawrence Livermore National Facility in the USA. Building on research performed as part of this project, UK researcher have also collaborated on new approaches to manufacture and characterisee focusing plasma optics.
Sectors Energy,Healthcare,Security and Diplomacy

 
Description The plasma-based optics developed through this project are impacting on the development of laser-driven particle and radiation sources and related physics, and thus potential long-term applications of these sources in a wide range of sectors. Due to their ability to sustain much higher amplitude fields, they are much more compact (more than a factor of ten reduction in the optic size) than solid state optics and importantly the ultrafast evolution of their optical properties also enables tailoring of other properties of the laser pulse. The findings of the research project are already being used in experiments on laser-driven particle sources at the Central Laser Facility and in the development of fast focusing optics for use at the European-scale ELI-Beamlines high power laser facility. The Strathclyde and CLF researchers involved in this project collaborated with a spin-out company at the University of Durham to manufacture and characterise the focusing plasma optics. Other research groups have since contacted the company to source these optics. There are potential long term benefits to UK industry via the development of laser-driven radiation sources and via the training of a post-doctoral researcher and PhD student, with a range of skills valued by both academia and industry. Members of the public have benefited via public outreach activities performed in the framework of the grant and from the dissemination of research outputs in a variety of formats. For example, the Nature Physics paper was featured in numerous scientific reports and popular press bulletins (including in Phys.org, Science Daily, Health Medicinet, AlphaGalileo, Space Daily, EurkAlert! and New Humanist Magazine).
First Year Of Impact 2014
 
Title Azimuthal asymmetry in collective electron dynamics in relativistically transparent laser-foil interactions 
Description "Asymmetry in the collective dynamics of ponderomotively-driven electrons in the interaction of an ultraintense laser pulse with a relativistically transparent target is demonstrated experimentally. The 2D profile of the beam of accelerated electrons is shown to change from an ellipse aligned along the laser polarization direction in the case of limited transparency, to a double-lobe structure aligned perpendicular to it when a significant fraction of the laser pulse co-propagates with the electrons. The temporally-resolved dynamics of the interaction are investigated via particle-in-cell simulations. The results provide new insight into the collective response of charged particles to intense laser fields over an extended interaction volume, which is important for a wide range of applications, and in particular for the development of promising new ultraintense laser-driven ion acceleration mechanisms involving ultrathin target foils. Dataset contains experimental data taken using the Astra-Gemini laser facility at the Rutherford Appleton Laboratory. Simulations were conducted using EPOCH code and the ARCHER supercomputer." 
Type Of Material Database/Collection of data 
Provided To Others? No  
Impact Not recorded 
 
Title Directed fast electron beams in ultraintense picosecond laser irradiated solid targets 
Description This data set relates to a paper accepted for publication in Applied Physics Letters, titled 'Directed fast electron beams in ultraintense picosecond laser irradiated solid targets'. The data is in *.txt formatted files and can be opened by any text viewer. The files associated with this data set are embargoed until the paper is published. 
Type Of Material Database/Collection of data 
Provided To Others? No  
Impact Not recorded 
 
Title Influence of low-temperature resistivity on fast electron transport in solids: scaling to fast ignition electron beam parameters 
Description "This dataset contains two types of files. These are: (1) *.dat files. These files contain the data plotted in the figures in the corresponding publication. Resinp_Li_caseA.dat, for example, is the resistivity curve for Li case A plotted in figure 1 of the paper. (2) *.in files. These files are the input files for the Zephyros code used to simulate the fast electron transport. The corresponding results for readin_Li_caseA.in, for example, are plotted in figure 2. This dataset relates to the EPSRC funded project Advanced laser-ion acceleration strategies towards next generation healthcare (EP/K022415/1) and the EPSRC funded research fellowship Multi-PetaWatt laser-Plasma Interactions: A New Frontier in Physics (EP/J003832/1). This dataset also relates to the publication 'Influence of low-temperature resistivity on fast electron transport in solids scaling to fast ignition electron beam parameters' published in the journal Plasma Physics and Controlled Fusion. 
Type Of Material Database/Collection of data 
Provided To Others? No  
Impact Not recorded 
 
Title Laser pulse propagation and enhanced energy coupling to fast electrons in dense plasma gradients 
Description "Dataset for a study of laser energy absorption to fast electrons during the interaction of an ultra-intense (1020 W cm-2), picosecond laser pulse with a solid as a function of the plasma density scale length. It is shown that there is an optimum density gradient for efficient energy coupling to electrons and that this arises due to strong self-focusing and channeling driving energy absorption over an extended length in the preformed plasma. At longer density gradients the laser filaments, resulting in significantly lower overall energy coupling. As the scale length is further increased, a transition to a second laser energy absorption process is observed experimentally via multiple diagnostics. The results demonstrate that it is possible to significantly enhance laser energy absorption and coupling to fast electrons by dynamically controlling the plasma density gradient. These results are of general importance for understanding absorption in laser-solid interactions but are specifically relevant for conditions where long plasma density scale lengths are expected such as in the corona of imploded targets in the fast ignition approach to inertial confinement fusion. Experimental and simulation data published in New Journal of Physics 16 (11), 113075. Experimental data was taken in April 2010 using the VULCAN-TAP laser facility at the Rutherford Appleton Laboratory. Simulations were conducted using the PRISM hydrodynamic code and EPOCH PIC code on the ARCHIE-west cluster." 
Type Of Material Database/Collection of data 
Provided To Others? No  
Impact Not recorded 
 
Title Optimisation of plasma mirror reflectivity and optical quality using double laser pulses 
Description The dataset is contained within an excel file. The file contains the data plotted in the figures in the corresponding paper. The study aimed to measure a record 962.5 % specularly reflected energy fraction from an interaction with a plasma mirror surface preionised by a controlled prepulse. Results determined that the optical quality is dependent on the inter pulse time delay. The files associated with this dataset are embargoed until 1 April 2015 and will be available here beyond this date. 
Type Of Material Database/Collection of data 
Provided To Others? No  
Impact Not recorded 
 
Title Proton acceleration enhanced by a plasma jet in expanding foils undergoing relativistic transparency 
Description This data set relates to a paper under review by the New Journal of Physics, titled 'Proton acceleration enhanced by a plasma jet in expanding foils undergoing relativistic transparency'. The zip file contains a readme file which explains the types of files included and the data they contain. It also contains details of simulation code and input files used to generate the data. The files associated with this data set are embargoed until the paper is accepted for publication. 
Type Of Material Database/Collection of data 
Provided To Others? No  
Impact Not recorded 
 
Description Central Laser Facility 
Organisation ELI Beamlines
Country Czech Republic 
Sector Private 
PI Contribution I am a user of high power laser facilities provided by these partners
Collaborator Contribution Provision of laser beam time
Impact Multiple research publications
Start Year 2012
 
Description Central Laser Facility 
Organisation Extreme Light Infrastructure - Nuclear Physics (ELI-NP)
Country Romania 
Sector Public 
PI Contribution I am a user of high power laser facilities provided by these partners
Collaborator Contribution Provision of laser beam time
Impact Multiple research publications
Start Year 2012
 
Description Central Laser Facility 
Organisation Helmholtz Association of German Research Centres
Department GSI Helmholtz Centre for Heavy Ion Research
Country Germany 
Sector Public 
PI Contribution I am a user of high power laser facilities provided by these partners
Collaborator Contribution Provision of laser beam time
Impact Multiple research publications
Start Year 2012
 
Description Central Laser Facility 
Organisation Rutherford Appleton Laboratory
Department Central Laser Facility
Country United Kingdom 
Sector Academic/University 
PI Contribution I am a user of high power laser facilities provided by these partners
Collaborator Contribution Provision of laser beam time
Impact Multiple research publications
Start Year 2012
 
Description Project partnership with Science and Technology Facilities Council (STFC) 
Organisation Science and Technologies Facilities Council (STFC)
Country United Kingdom 
Sector Public 
PI Contribution Science and Technology Facilities Council (STFC) worked with the research team and assisted/contributed to the project outcomes
Start Year 2013
 
Description Project partnership with Shanghai Jiao Tong University 
Organisation Shanghai Jiao Tong University
Country China 
Sector Academic/University 
PI Contribution Shanghai Jiao Tong University worked with the research team and assisted/contributed to the project outcomes
Start Year 2013
 
Description GSI mbH, PHELIX Dept 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact PI on an experiment using the PHELIX laser at GSI in January 2018
Year(s) Of Engagement Activity 2018
 
Description GSI mbH, PHELIX Dept 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact PI on an experiment using the PHELIX laser at GSI in February 2017
Year(s) Of Engagement Activity 2017
 
Description Invited Talk - Laserlab-Europe conference/meeting in Lisbon 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Invited Talk - Laserlab-Europe conference/meeting in Lisbon
Year(s) Of Engagement Activity 2017
 
Description Invited Talk at an EPS Conference Satellite International Workshop on High Field Science 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Invited Talk at an EPS Conference Satellite International Workshop on High Field Science
Year(s) Of Engagement Activity 2017
 
Description Invited Talk at an EPS Conference Satellite International Workshop on High Field Science 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Invited Talk at an EPS Conference Satellite International Workshop on High Field Science
Year(s) Of Engagement Activity 2017
 
Description Invited lecture at the 2016 Culham Summer School 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Invited lecture at the 2016 Culham Summer School
Year(s) Of Engagement Activity 2016
 
Description Invited lecture at the 2016 Culham Summer School 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Invited lecture at the 2016 Culham Summer School
Year(s) Of Engagement Activity 2016
 
Description Invited research seminar at Chalmers University 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Invited research seminar at Chalmers University
Year(s) Of Engagement Activity 2016
 
Description Invited seminar (Plasma Physics Group) at GSI, Darmstadt 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact n/a
Year(s) Of Engagement Activity 2015
 
Description Invited seminar (Plasma Physics Group) at GSI, Darmstadt 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact n/a
Year(s) Of Engagement Activity 2015
 
Description Invited seminar at the Lund Laser Centre 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Invited seminar at the Lund Laser Centre
Year(s) Of Engagement Activity 2016
 
Description Invited seminar at the University of Oxford: Self-generated current structures in relativistic laser-solid interactions 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact discussion
Year(s) Of Engagement Activity 2014
 
Description Invited talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Invited seminar: Self-generated current structures in relativistic laser-solid interactions
Year(s) Of Engagement Activity 2014
 
Description Invited talk - Central Laser Facility 40th Anniversary Meeting 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Invited talk - Central Laser Facility 40th Anniversary Meeting
Year(s) Of Engagement Activity 2017
 
Description Invited talk at Cockcroft Institute PhD conference 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Invited talk at Cockcroft Institute PhD conference
Year(s) Of Engagement Activity 2017
 
Description Invited talk at Cockcroft Institute Scientific Advisory Committee Meeting 2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Invited talk at Cockcroft Institute Scientific Advisory Committee Meeting 2017
Year(s) Of Engagement Activity 2017
 
Description Invited talk at Cockcroft Institute Scientific Advisory Committee Meeting 2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Invited talk at Cockcroft Institute Scientific Advisory Committee Meeting 2017
Year(s) Of Engagement Activity 2017
 
Description Invited talk at the 2nd Conference on Extremely High Intensity Laser Physics (2017) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Invited talk at the 2nd Conference on Extremely High Intensity Laser Physics (2017)
Year(s) Of Engagement Activity 2017
 
Description Invited talk at the 2nd International Symposium on High Power Laser Science and Engineering (HPLSE2016). 
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 Invited talk at the 2nd International Symposium on High Power Laser Science and Engineering (HPLSE2016).
Year(s) Of Engagement Activity 2016
 
Description Invited talk at the Cockcroft Institute 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Invited talk at the Cockcroft Institute
Year(s) Of Engagement Activity 2016
 
Description Invited talk at the International Conference on Ultrafast Optical Science (UltrafastLIght-2017) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Invited talk at the International Conference on Ultrafast Optical Science (UltrafastLIght-2017)
Year(s) Of Engagement Activity 2017
 
Description Invited talk on ion acceleration at the Central Laser Facility 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact n/a
Year(s) Of Engagement Activity 2014
 
Description SUPA Annual Gathering 2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact May 2017 SUPA Annual Gathering
Year(s) Of Engagement Activity 2017