Plasma based particle accelerators driven by either lasers are the future of the particle accelerators technology, due to the fact, that this technology can overcome the limit of the standard accelerators given by the physicalchemical properties of the material used for the construction as well as by the huge size and the financial costs. Nevertheless, a stable synchronization of the electron bunch and of the plasma wakefield in the range of few femtoseconds is necessary in order to optimize the acceleration. Therefore, for SINBAD a shot to shot synchronization system is planned, that should be able to synchronize the electron bunch with the plasma exciting laser pulse with a time resolution of less than 1 fs. In a first step, stable Terahertz (THz) pulses should be performed by optical rectification of high energy laser pulses in a nonlinear crystal. These pulses allow an energy modulation of the electron bunch in order to achieve the required resolution This paper focuses on the first step of the feedback system, i.e. the generation of THz pulses using a periodically poled lithium niobate crystal LiNbO3 (PPLN) and we investigate the in uence of the optical properties of the material on the stability and efficiency of this process. We present systematic calculations of the optical properties of the crystal and of their in uence on the efficiency and on the optimum crystal length for the generation of THz pulses. We compare different models and approximation for the dielectric function (full Sellmeier equation or linear approximation, FC implementation or neglecting, different description of the FC saturation, depletion of the pump) and different modeling of the generation dynamic (full second order calculation or first order slope varying approximation) in order to obtain a detailed diagnostic for the THz generation and to optimize our feedback system.
Plasma based particle accelerators driven by either lasers or particle beams are most probably the future of the particle accelerators technology. In a laser driven plasma based particle accelerators a stable synchronization of the electron bunch and of the plasma wake field in the range of less than 2 fs is necessary in order to optimize the acceleration. For this purpose we are developing a new shot to shot feedback system with a time resolution of less than 1 fs. As a first step, stable THz pulses are generated by optical rectification of a fraction of the plasma generating high energy laser pulses in a nonlinear lithium niobate crystal. It is planed that the generated THz pulses will energy modulate the electron bunches shot to shot before the plasma to achieve the time resolution. In this contribution we systematically investigate the influence of the optical properties as well as the theoretical description of the THz generation on the conversion efficiency of the generation of short THz pulses. We compare different approximations for the modeling of the generation dynamics (full second order calculation or first order slope varying approximation SVA) and of the dielectric function (linear approximation of the dispersion relation, influence of the free carries generated by the pump adsorption and their saturation, decreasing of the pump intensity) in order to investigate the importance of a detailed description of the optical properties.
Plasma-based particle accelerators driven by either lasers or particle beams are an important new technology in order to reduce the large size of conventional accelerators and to minimize the construction costs. Using laser driven plasma wakefield accelerators, the synchronization between electron bunch and the ultrashort laser is crucial to obtain a stable acceleration. In order to minimize the electron bunch arrival-time jitter, the development of a new shot to shot feedback system with a time resolution of less than 1 fs is planned. As a first step, stable Terahertz pulses (THz pulses) should be performed by optical rectification of high energy femtosecond laser pulses in a nonlinear crystal. It is planed that the generated THz pulses will energy modulate the electron bunches shot to shot before the plasma to achieve the time resolution of 1fs. The selection of the nonlinear material for optical reptification is a critical aspect for the development of laser driven THz sources. In this contribution we systematically investigate the influence of the optical properties, and in particular adsorption coefficient of lithium niobate crystal as well as the theoretical description of the THz generation on the conversion efficiency of the generation of short THz pulses.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.