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It is presented that the thermally induced transmitted wavefront aberration of a high-reflectivity sampling mirror was detected on line using a Shack-Hartmann wavefront sensor (SHWS) in the beam quality measurement of an intense laser. As a result of heat absorption in the sampling mirror with active aperture of 120 mm, thermally induced wavefront aberration emerged when the mirror was exposed to high laser intensity of several kilowatts per centimeter square. Time-dependent wavefront aberration curves were acquired, and the transmitted wavefronts were reconstructed based on Zernike mode reconstruction theory. The experimental results indicate that the magnitude of the dynamic transmitted wavefront aberration increases gradually with the growing heat deposit during laser irradiation. The maximum of wavefront aberration observed after irradiation for 5 seconds reaches 0.11 μm of root-mean-square value. After further analysis, the experimental results of dynamic aberration can be applied in modifications for the measurement results of intense laser beam quality or tests for the thermal stability of optics used in the intense laser systems.

A broad bandwidth analog fiber optic link is developed for ultra-fast signal transmission under the circumstance with complicated electromagnetic fields. The electrical ultra-fast signal is converted to optical ones by electro-optic conversion method which operates via amplitude modulation mechanism. With several kilometers distance transmission, the optical signal is recovered by photo-electric conversion method correspondingly. The measurement results of the link indicate that its bandwidth is (0.0003-3)GHz, in-band flatness ±1dB, linear dynamic range 40dB, output peak-to-peak noise within 5mV, both of input and output standing-wave-ratios less than 2. It's applied in high power microwave experiments. The experimental results show that the 3GHz analog fiber optic link which employs electro-optic and photo-electric conversion techniques is suitable for ultra-fast pulse signals transmission. It greatly improves the bandwidth margin of the diagnosis system.