飞秒超短脉冲激光对硅太阳能电池的损伤阈值研究

首次采用飞秒超短脉冲激光（35 fs），研究其对硅太阳能电池的损伤阈值。与相同波长的连续激光对比，飞秒激光的损伤阈值略高。这一结果不同于纳秒或皮秒激光，主要是因为当加热脉冲时间相当或小于电子-声子耦合时间时，非热平衡效应显著，热传导现象不再满足Fourier 定律。在实验中采用了光束整形技术，首次采用强度均匀分布的激光研究损伤阈值。此技术能减小高斯激光中心光强过大造成的实验偏差。

Damage threshold research of monocrystalline silicon solar cells under femtosecond laser illumination

Femtosecond laser with ultrashort pulse (35 fs) was first applied to investigate damage threshold of a monocrystalline silicon solar cell. Compared with a continuous-wave laser of the same central wavelength, a femtosecond laser pulse was found to have a slightly higher damage threshold. Unlike nanosecond or picosecond lasers, the femtosecond laser has heating pulse time equal to or shorter than the electron- phonon coupling time. Thus, the thermal non-equilibrium effect becomes obvious, and the heat conduction phenomenon no longer meets the law of Fourier. In the damage threshold experiments, a beam shaping technique was applied for a femtosecond laser to generate uniform intensity distribution, which could prevent experimental deviation caused by great concentrated intensity distribution of a conventional laser pulse with the Gaussian profile.