HARMONI - first light spectroscopy for the ELT: final design of the integral field unit

Proceedings of SPIE--the International Society for Optical Engineering SPIE, the international society for optics and photonics 11451 (2020) 1145138-1145138-11

Authors:

Magali Loupias, Johan Richard, Alban Remillieux, Jean-Emmanuel Migniau, Florence Laurent, Alexandre Jeanneau, Karen Disseau, Eric Daguise, Diane Chapuis, Didier Boudon, Nicolas Bouché, Hermine Schnetler, Ian Bryson, Dave Melotte, Angus Gallie, Niranjan A Thatte, Fraser Clarke, Matthias Tecza, Edgard Renault, Johan Kosmalski

HARMONI - first light spectroscopy for the ELT: novel techniques for the calibration of non-common path aberrations

SPIE, the international society for optics and photonics (2020) 349

Authors:

Alvaro Menduina, Matthias Tecza, Niranjan Thatte

HARMONI first light spectroscopy for the ELT: geometrical calibration in the data reduction software

Proceedings of SPIE--the International Society for Optical Engineering SPIE, the international society for optics and photonics 11452 (2020) 114522t-114522t-16

Authors:

Laure Piqueras, Aurélien Jarno, Louise Friot-Giroux, Thomas Béchet, Javier Piqueras López, Arlette Pécontal, Johan Richard, Nicolas Bouché, Niranjan A Thatte, Matthias Tecza

HARMONI: Characterising the line-spread-function with a tunable Fabry-Pérot etalon

Proceedings of SPIE--the International Society for Optical Engineering SPIE, the international society for optics and photonics 11451 (2020) 114515w-114515w-6

Authors:

Darshan Kakkad, Matthias Tecza, Niranjan A Thatte, Javier Piqueras López, Harry Kendell

Automation and control of laser wakefield accelerators using Bayesian optimization

Nature Communications Nature Research 11:1 (2020) 6355

Authors:

Rj Shalloo, Sjd Dann, J-N Gruse, Cid Underwood, Af Antoine, C Arran, M Backhouse, Cd Baird, Md Balcazar, N Bourgeois, Ja Cardarelli, Peter Hatfield, J Kang, K Krushelnick, Spd Mangles, Cd Murphy, N Lu, J Osterhoff, K Põder, Pp Rajeev, Cp Ridgers, S Rozario, Mp Selwood, Aj Shahani, Dr Symes, Agr Thomas, C Thornton, Z Najmudin, Mjv Streeter

Abstract:

Laser wakefield accelerators promise to revolutionize many areas of accelerator science. However, one of the greatest challenges to their widespread adoption is the difficulty in control and optimization of the accelerator outputs due to coupling between input parameters and the dynamic evolution of the accelerating structure. Here, we use machine learning techniques to automate a 100 MeV-scale accelerator, which optimized its outputs by simultaneously varying up to six parameters including the spectral and spatial phase of the laser and the plasma density and length. Most notably, the model built by the algorithm enabled optimization of the laser evolution that might otherwise have been missed in single-variable scans. Subtle tuning of the laser pulse shape caused an 80% increase in electron beam charge, despite the pulse length changing by just 1%.