Recently, techniques involving random patterns have made it possible to control the light trapping of microstructures over broad spectral and angular ranges, which provides a powerful approach for photon management in energy efficiency technologies. Here, we demonstrate a simple method to create a wideband near-unity light absorber by introducing a dense and random pattern of metal-capped monodispersed dielectric microspheres onto an opaque metal film; the absorber works due to the excitation of multiple optical and plasmonic resonant modes. To further expand the absorption bandwidth, two different-sized metal-capped dielectric microspheres were integrated into a densely packed monolayer on a metal back-reflector. This proposed ultra-broadband plasmonic-photonic super absorber demonstrates desirable optical trapping in dielectric region and slight dispersion over a large incident angle range. Without any effort to strictly control the spatial arrangement of the resonant elements, our absorber, which is based on a simple self-assembly process, has the critical merits of high reproducibility and scalability and represents a viable strategy for efficient energy technologies.

The radiochromic film (RCF) is a high-dose, high-dynamic range dosimetry detection medium. A stack of RCFs can be used to detect both spatial and energetic distribution of laser driven ion beams with a large divergence angle and continuous energy spectrum. Two types of RCFs (HD-V2 and MD-V3, from Radiation Products Design, Inc.) have been calibrated using MeV energy protons and carbon ions produced by using a 2 × 6 MV tandem electrostatic accelerator. The proportional relationship is obtained between the optical density and the irradiation dose. For protons, the responses are consistent at all energies with a variation of about 15%. For carbon ions, the responses are energy related, which should be noted for heavy ion detection. Based on the calibration, the broad energy spectrum and charge distribution of laser accelerated proton beam with energy from 3 to 8 MeV and pC charge were detected and reconstructed at the Compact LAser Plasma Accelerator at Peking University.

A compact laser plasma accelerator (CLAPA) that can stably produce and transport proton ions with different energies less than 10 MeV, <1% energy spread, several to tens of pC charge, is demonstrated. The high current proton beam with continuous energy spectrum and a large divergence angle is generated by using a high contrast laser and micron thickness targets, which later is collected, analyzed and refocused by an image-relaying beam line using a combination of quadrupole and bending electromagnets. It eliminates the inherent defects of the laser-driven beams, realizes precise manipulation of the proton beams with reliability, availability, maintainability and inspectability (RAMI), and takes the first step towards applications of this new generation of accelerator. With the development of high-rep rate Petawatt (PW) laser technology, we can now envision a new generation of accelerator for many applications in the near future soon.