Schmidhammer Uli, Jeunesse Pierre, Stresing Gerhard, Mostafavi Mehran
Laboratoire de Chimie Physique/ELYSE, UMR 8000 CNRS/Université Paris-Sud 11, Faculté des Sciences d'Orsay, Orsay Cedex 91405, France.
Appl Spectrosc. 2014;68(10):1137-47. doi: 10.1366/13-07214. Epub 2014 Oct 1.
We present a new development for pump-probe absorption spectroscopy that allows the simultaneous measurement from the green part of the visible spectrum (510 nm) over the whole near-infrared range to >1600 nm, corresponding to 0.77-2.40 eV. The system is based on a sub-picosecond supercontinuum generated in bulk material used as a broadband probe that is dispersed with a custom-made prism spectrometer and detected by an InGaAs array with extended sensitivity to the visible. Two versions, with and without probe referencing, are implemented for operation at laser repetition rates of a few hertz and kilohertz, respectively. After presentation of the optical configuration of the spectrometer, its performance is characterized and further illustrated on two time scales, with the ultrafast radiolysis of isopropanol induced by a picosecond electron pulse and with the instantaneous response of a BK7 plate to a femtosecond light pulse. The photophysics of the dye IR-140 is resolved from the femto- to picosecond regime. Stable and easy day-to-day routine use of the spectrometer also can be achieved in non-optical laboratory surroundings. For operation in a hazardous environment, the optical probe beams can be transported to the detector unit by optical fibers.
我们展示了泵浦 - 探测吸收光谱技术的一项新进展，该技术能够同时测量从可见光谱的绿色部分（510纳米）到整个近红外范围直至大于1600纳米，对应能量为0.77 - 2.40电子伏特。该系统基于在用作宽带探测的块状材料中产生的亚皮秒超连续谱，通过定制的棱镜光谱仪进行色散，并由对可见光具有扩展灵敏度的铟镓砷（InGaAs）阵列进行检测。分别实现了带和不带探测参考的两个版本，以分别在几赫兹和千赫兹的激光重复频率下运行。在介绍了光谱仪的光学配置后，对其性能进行了表征，并在两个时间尺度上进一步说明，一个是皮秒电子脉冲诱导异丙醇的超快辐射分解，另一个是BK7平板对飞秒光脉冲的瞬时响应。染料IR - 140的光物理过程在从飞秒到皮秒的时间范围内得到解析。在非光学实验室环境中也能够实现光谱仪稳定且日常易于操作的使用。对于在危险环境中的操作，光学探测光束可以通过光纤传输到探测器单元。
