Recent progress on staging laser-plasma accelerators

Recent progress on a staged laser-plasma accelerator (LPA) experiment is reported. The experiment utilizes a 40 TW class laser which is split into two laser pulses. The first laser drives the first LPA module to produce an electron beam. The second laser drives the second LPA module in a dark-current free regime and accelerates the electron beam from the first LPA. Injection from the first stage, triggering of plasma mirror and reflection of the second laser, and laser guiding in the second stage with the laser pulses reflected off the plasma mirror has been successfully demonstrated. Optical spectral redshift of driving laser is analyzed to estimate the wakefield amplitude and electron energy gain in the second stage.