Shaped liquid drops generate MeV temperature electron beams with millijoule class laser

• Published in: Communications physics 2024-03, Vol.7 (1), p.85-10, Article 85
• Main Authors: Mondal, Angana, Sabui, Ratul, Tata, Sheroy, Trines, R. M. G. M., Rahul, S. V., Li, Feiyu, Sarkar, Soubhik, Trickey, William, Kumar, Rakesh Y., Rajak, Debobrata, Pasley, John, Sheng, Zhengming, Jha, Jagannath, Anand, M., Gopal, Ram, Robinson, A. P. L., Krishnamurthy, M.
• Format: Article
• Language: English
• Subjects: 639/766/1960/1135; 639/766/1960/1137; Droplets; Drops (liquids); Electron beams; Electron energy; Electron sources; Electrons; Hot electrons; Lasers; Physics; Physics and Astronomy; Plasma waves
• ISSN: 2399-3650; 2399-3650
• DOI: 10.1038/s42005-024-01550-8

MeV temperature electrons are typically generated at laser intensities of 10 18 W cm −2 . Their generation at non-relativistic intensities (~10 16 W cm −2 ) with high repetition rate lasers is cardinal for the realization of compact, ultra-fast electron sources. Here we report a technique of dynamic target structuring of micro-droplets using a 1 kHz, 25 fs, millijoule class laser, that uses two collinear laser pulses; the first to create a concave surface in the liquid drop and the second, to dynamically-drive electrostatic plasma waves that accelerate electrons to MeV energies. The acceleration mechanism, identified as two plasmon decay instability, is shown to generate two beams of electrons with hot electron temperature components of 200 keV and 1 MeV, respectively, at an intensity of 4 × 10 16 Wcm −2 , only. The electron beams are demonstrated to be ideal for single shot high resolution (tens of μ m) electron radiography. Typically, mJ lasers generate 50 keV temperature plasma electrons. Here, the authors use mJ laser pulses to chisel a liquid droplet surface and generate an electron temperature of 1 MeV, a feat previously possible only with 100 times more powerful lasers.