Convenient pulse length measurement of sub-20-fs pulses down to the deep UV via two-photon absorption in bulk material
Convenient pulse length measurement of sub-20-fs pulses down to the deep UV via two-photon absorption in bulk material
复制标题
通过散装材料中的双光子吸收，方便地测量低至深紫外的亚 20 飞秒脉冲的脉冲长度
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
E. Riedle
中科院分区：
文献类型：
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作者：
C. Homann;N. Krebs;E. Riedle
利用薄晶体和玻璃板中双光子吸收的光束衰减，直接测量了紫外飞秒脉冲的强度自相关，而不需要辅助脉冲。我们给出了一个完整的描述，新开发的设置操作从蓝色到深紫外。研究了实现可靠测量所必须满足的条件。双光子吸收材料的选择决定了可实现的波长范围，材料厚度决定了可以可靠表征的最短脉冲，高强度影响了由于饱和效应而衍生的脉冲持续时间。在持续时间低于20fs、能量为3nj、中心波长从可见光到195nm的脉冲中，证明了紫外自相关器的性能，在激光重复频率为1khz时实现了2hz的更新速率。通过z-扫描测量确定了BBO双光子吸收系数的波长依赖性，我们发现它在较长波长处的下降速度比线性吸收光谱预期的要快得多。
The beam attenuation by two-photon absorption in thin crystals and glass plates is utilized for directly measuring the intensity autocorrelation of UV femtosecond pulses without the need for an auxiliary pulse. We give a full description of the newly developed setup for operation from the blue down to the deep UV. The conditions that must be met to achieve reliable measurements are investigated. The choice of the two-photon-absorbing material governs the attainable wavelength range, the material thickness determines the shortest pulse that can be reliably characterized and high intensities influence the derived pulse duration due to saturation effects. The performance of the UV autocorrelator is demonstrated for pulses with durations below 20 fs, with energies of 3 nJ and with central wavelengths from the visible down to 195 nm. 2-Hz update rates are achieved at the 1-kHz repetition rate of the laser. The wavelength dependence of the two-photon-absorption coefficient of BBO is determined by z-scan measurements and we find that it decreases much faster at longer wavelengths than is expected from the linear absorption spectrum.