Description
Most schemes for IFE are based on solid state lasers, and they use the third harmonics of Nd:YAG. A promising alternative of solid state laser systems is the excimer laser, as ELECTRA or the scheme suggested by the XCIMER company The short wavelengths and broad bandwidth of excimer lasers are preferential parameters to avoid parametric instabilities. Excimers have intrinsically shorter wavelengths, and their overall gain bandwidth can surpass that can be produced by harmonic conversion of IR pulses. Herewith we propose a scheme for broadband KrF laser systems which helps to mitigate nonlinear phenomena. Due to gain narrowing the typical laser bandwidth of a free running oscillator is an order of magnitude less than the overall gain width. We propose a scheme in which several laser oscillators are detuned from each other. This can be realized in a single oscillator surrounded with multiple, detuned resonators, thus making synchronization easier. After amplification in separate preamplifiers the narrow bandwidth pulses are unified and then amplified in the main amplifiers. In this approach besides the temporal incoherence of the pulse even the spatial incoherence will not require the use of ISI schemes. The calculations show that an output pulse of 1 nm bandwidth can be obtained with a smooth spectral shape, serving as a potential candidate for the KrF alternative in IFE.
This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No 101052200 — EUROfusion). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. The involved teams have operated within the framework of the Enabling Research Project CfP-FSD-AWP26-ENR-01 “Conceptual design for a European High Power Laser Fusion Research Facility”. The project also received funding from the National Research, Development, and Innovation Office (OTKA K138339 project) of Hungary.