Enhanced Hot-Electron Production from Compound Parabolic Concentrator Targets on a Short-Pulse, High-Contrast Laser System

The production of hot-electrons from high-intensity laser interactions is the key to the development of high energy particle and photon sources. The acceleration of the hot-electron population is proportional to the incident laser intensity. The highest intensities are often achieved via a final short focal length focusing optic. However, the development of miniature targetry and 3D printing has opened the door to a cheap and effective alternative. Cone targets can therefore be fabricated such they operate as a plasma optic. We on compound parabolic concentrator (CPC) [1] targets that geometrically increase the intensity on target. Experimental measurements were made at the Texas Petawatt laser facility with a short-pulse (150 fs) high-intensity (10$^{\mathrm{18}}$ W/cm2) and long focal length (F/40). We report a hot-electron temperature enhancement of approximately a factor of 7 from the CPC target when compared to planar target. Using PIC simulations, we describe this hot-electron enhancement from a purely geometric intensity enhancement and existing temperature-intensity scaling laws.