讲座题目：Novel approaches in multidimensional spectroscopy.Spectroscopy with phase modulated light fields and stochastic light spectroscopy.
主讲人：Vladimir Osipov
主持人：康斯坦丁研究员
报告时间：2019.3.15. 上午10：00
报告地点：理科大楼A814室
报告摘要：
Coherent multidimensional spectroscopy has drawn much attention as a tool of optical imaging. It produces spectra that show the magnitude of an optical signal as a function of two or more pulsed laser frequencies. In conventional 2D spectroscopy three noncollinear laser pulses interact with matter and generate a coherent signal in phase matched directions. Analysis of the signal at various time delays between the pulses provides information about quantum pathways and energy dissipation of the system. Constant improvement of experimental techniques and increasing complexity of objects under investigation requires extension of methods. Two novel spectroscopy methods will be discussed in the talk.
Contrary to the conventional multidimensional spectroscopy in the phase modulated spectroscopy approach all light beams are collinear, while the base frequencies of pulses are acoustically modulated by a number of phases φ1, φ2,.. Intensity of such light transmitted through a sample gains a number of new acoustic harmonics at different combinations of φ’s.Thus the spatial separation of signals in the original 2D scheme is replaced by filtering of certain Fourier components. Detection of the harmonics and their relative amplitudes provide information on the light-matter interaction pathways, while periodic repetition of the process allows to improve the signal to noise ratio. We showed that the approach allows to reveal and quantify the type of relaxation kinetics taking place in the sample after photo-excitation [1].
In the stochastic light spectroscopy the covariance spectrum obtained by averaging of the covariance signal at two different frequencies is the central object of analysis. The covariance spectrogram is obtained by averaging of the transmited broadband stochastic probe-light undergoing a nonlinear optical process with matter. The covariance spectrogram features can be interpret using first and the second-order intensity correlation functions of the probe pulse. Application is made to transient absorption and stimulated Raman signals, where the ultraviolet pump and delayed stochastically-modulated infrared or optical Raman probe are used for monitoring vibrational excitations. Stochastic light can circumvent the limitations on the joint temporal and spectral resolution of the signal. The method is applied to the model system with a time-dependent frequency switch [2].
[1] V.Al.Osipov, X.Shang, T.Hansen, T.Pullerits, K.J.Karki, “Nature of relaxation processes revealed by the
action signals of intensity-modulated light fields” Phys.Rev.A 94 (2016) 053845
[2] V.Al.Osipov, S.S.Asban, S.Mukamel, “Time and frequency resolved transient absorption and stimulated
Raman signals with stochastic light” To be submitted (2019)
报告人简介：
Education
PhD in Physical and Mathematical Sciences
10.10.2003 N.N.Semenov Institute of Chemical Physics of the Russian Academy of Sciences,
Russia; Supervisor: Dr. Vladik A. Avetisov; Department of Structure of Matter
Thesis: p-Adic models of ultrametric diusion and their application to the description of protein conformational dynamics.
MSc Diploma of engineer physicist in nuclear physics
19.02.1998 Moscow State Engineering-Physics Institute, Russia; Supervisor: Prof. Dr. Michael
I. Ryazanov; Department of Theoretical Nuclear Physics
Thesis: Emission of a charge moving uniformly parallel to the surface of a nonstationary medium.
Employment: Research
2018 - 20 Associate Specialist
Department of Chemistry, University of California, Irvine, USA.
2015 - 2017 Postdoctoral Associate
Department of Chemical Physics, Lund University, Lund, Sweden.
2014 - 2015 Distinguished position
Department of Physics, Duisburg-Essen University, Duisburg, Germany.
2011 - 2013 Research Associate
Institute of Theoretical Physics, Cologne University, Cologne, Germany.
Germany excellence university from 2012
2008 - 2011 Research Associate
Department of Physics, Duisburg-Essen University, Duisburg, Germany.
2005 - 2008 Postdoctoral Associate
Department of Applied Mathematics, H.I.T. { Holon Institute of Technology,
Holon, Israel.
1998 - 2005 Engineer, Researcher
V.I. Goldanskii Department of Structure of Matter,
N.N. Semenov Institute of Chemical Physics, Russ.Ac.Sci.