Abstract:
Background With the continuous development of national strategic needs, multiple large-scale radiation simulation facilities have been constructed, imposing increasingly stringent requirements on the temporal and spatial resolution of radiation detection. Researchers have been actively developing novel techniques to achieve higher resolution. Against this background, the technique utilizing the transient refractive index response of semiconductor crystals for radiation detection has gained significant attention.
Purpose This study presents a novel approach based on refractive index changes in indium phosphide (InP) crystals to enhance the temporal and spatial resolution of radiation detection. A proof-of-principle experiment was conducted to validate the effectiveness of the proposed technique for pulsed radiation detection.
Methods A radiation imaging system was constructed based on a Michelson interferometer configuration. This system used a 350 μm thick iron-doped InP crystal as the radiation sensor.
Results Using this setup, images of refractive index changes within the crystal induced by laser pulse excitation with a wavelength of 532 nm were successfully captured. Pump-probe measurements revealed that the iron-doped InP crystal exhibited a time response of 1.5 ns under pump laser irradiation. Spatial resolution was characterized by placing a resolution target in the pump beam path; image reconstruction achieved a system spatial resolution of 1 lp/mm.
Conclusions These experimental results demonstrate the feasibility of the ultrafast image detection technology based on InP refractive index changes. This system has the potential to significantly advance pulsed radiation beam detection technology, offering high temporal and spatial resolution capabilities.
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