Johansson Jonas, Berg Roger, Pifferi Antonio, Svanberg Sune, Björn Lars Olof
Department of Atomic Physics, Lund Institute of Technology, Lund, SwedenDivision of Plant Physiology, Lund University, Lund, Sweden.
Photochem Photobiol. 1999 Feb;69(2):242-247. doi: 10.1111/j.1751-1097.1999.tb03281.x.
Abstract- Time-resolved transmittance was used to extract in vivo optical properties of leaves of green plants experimentally. In time-resolved transmittance measurements an ultrashort light pulse is directed onto the surface of the object and the transmitted light is measured with a time resolution in the range of picoseconds. A table-top terawatt laser was used to generate 200 fs light pulses at 790 nm with a repetition rate of 10 Hz. The light pulses were focused through a cuvette filled with water to produce white light pulses and optical filters were placed in the beam path to select the wavelength of the light focused onto the leaf surface. The time profiles of the light transmitted through the leaves was recorded with a streak camera having a time resolution of about 2.5 ps. Results from Crassula falcata and Phaseolus vulgaris studied at 550, 670 and 740 nm are reported. The three selected wavelength regions represent medium, high and a low absorption of light, respectively. A library of curves was generated using Monte Carlo simulation, and the absorption and scattering coefficients were extracted by comparison of experimental curves with this library. Our results suggest that in the case of the thin (200 μm) Phaseolus leaves and certainly in the case of the thick (4 mm) Crassula leaves, light scattering plays an important role in light transport through the leaf and should also affect light flux in these leaves.
摘要——采用时间分辨透射率实验提取绿色植物叶片的体内光学特性。在时间分辨透射率测量中，将超短光脉冲照射到物体表面，并以皮秒级的时间分辨率测量透射光。使用台式太瓦激光在790nm处产生200fs的光脉冲，重复频率为10Hz。光脉冲通过装满水的比色皿聚焦以产生白光脉冲，并在光路中放置光学滤波器以选择聚焦在叶片表面的光的波长。用时间分辨率约为2.5ps的条纹相机记录透过叶片的光的时间分布。报告了在550、670和740nm处对景天科植物和菜豆进行研究的结果。所选的三个波长区域分别代表光的中等、高和低吸收。使用蒙特卡罗模拟生成了一个曲线库，并通过将实验曲线与该库进行比较来提取吸收系数和散射系数。我们的结果表明，对于薄（200μm）的菜豆叶片，当然对于厚（4mm）的景天科植物叶片，光散射在光通过叶片的传输中起着重要作用，并且也应该影响这些叶片中的光通量。
