UV Laser Beam Profilers Based on CVD Diamond

Abstract

1D and 2D detector arrays have been realized on 270 μm thick 10 × 10 mm² CVD diamond samples. The relatively high resistivity of diamond specimens in the dark (>3 × 10¹² Ωcm) allowed the fabrication of photoconductive “sandwich” pixel-detectors. For both the structures, a semitransparent light-receiving back-side contact was used for detector biasing. Cross-talk between pixels was limited by using intermediate guard contacts connected at the same ground potential of the pixels. Each pixel photocurrent was conditioned by a read-out electronics composed by a high sensitive integrator and a σ- δADC converter. The overall 500 μs conversion time allowed a data acquisition rate up to 2kSPS. The measured fast photoresponse of the diamond samples in the nano second time regime suggests to use the proposed devices for fine tuning feedback of high-power pulsed-laser cavities, whereas the solar-blindness guarantees high performance in UV beam diagnostics also under high intensity background illumination.