The increasing demand for high laser powers is placing huge demands on current laser technology. This is now reaching a limit, and to realise the existing new areas of research promised at high intensities, new cost-effective and technically feasible ways of scaling up the laser power will be required. Plasma-based laser amplifiers may represent the required breakthrough to reach powers of tens of petawatt to exawatt, because of the fundamental advantage that amplification and compression can be realised simultaneously in a plasma medium, which is also robust and resistant to damage, unlike conventional amplifying media. Raman amplification is a promising method, where a long pump pulse transfers energy to a lower frequency, short duration counter-propagating seed pulse through resonant excitation of a plasma wave that creates a transient plasma echelon that backscatters the pump into the probe. Here we present the results of an experimental campaign conducted at the Central Laser Facility. Pump pulses with energies up to 100 J have been used to amplify sub-nanojoule seed pulses to near-joule level. An unprecedented gain of eight orders of magnitude, with a gain coefficient of 180 cm−1 has been measured, which exceeds high-power solid-state amplifying media by orders of magnitude. High gain leads to strong competing amplification from noise, which reaches similar levels to the amplified seed. The observation of 640 Jsr−1 directly backscattered from noise, implies potential overall efficiencies greater than 10%.
Gregory Vieux, Silvia Cipiccia, Nuno R. C. Lemos, Cristian Ciocarlan, Peter A. Grant, David W. Grant, Bernhard Ersfeld, MinSup Hur, Panagiotis Lepipas, Grace Manahan, David Reboredo Gil, Anna Subiel, Gregor H. Welsh, S. Mark Wiggins, Samuel R. Yoffe, John P. Farmer, Constantin Aniculaesei, Enrico Brunetti, Xue Yang, Robert Heathcote, Gagik Nersisyan, Ciaran L. S. Lewis, Alexander Pukhov, Joāo Mendanha Dias, and Dino A. Jaroszynski, "Laser amplifier based on Raman amplification in plasma (Conference Presentation)," Proc. SPIE 10234, Relativistic Plasma Waves and Particle Beams as Coherent and Incoherent Radiation Sources II, 1023407 (Presented at SPIE Optics + Optoelectronics: April 27, 2017; Published: 13 June 2017); https://doi.org/10.1117/12.2269511.5463398345001.
Conference Presentations are recordings of oral presentations given at SPIE conferences and published as part of the conference proceedings. They include the speaker's narration along with a video recording of the presentation slides and animations. Many conference presentations also include full-text papers. Search and browse our growing collection of more than 12,000 conference presentations, including many plenary and keynote presentations.