倪宏程 超快光学、阿秒物理、强场物理、原子分子光物理理论青年研究员（紫江青年****）
精密光谱科学与技术国家重点实验室??????


导航
个人资料
研究方向
开授课程
科研项目
学术成果
荣誉及奖励







个人资料
部门： 精密光谱科学与技术国家重点实验室
毕业院校： 美国科罗拉多大学
学位： 博士
学历： 博士研究生
邮编： 200241
联系电话：
传真：
电子邮箱： hcni@lps.ecnu.edu.cn
办公地址： 光学大楼A305
通讯地址： 上海市闵行区东川路500号

教育经历
2004.09--2008.06 南京大学 理学学士
2008.08--2014.06 美国科罗拉多大学 理学博士

工作经历
2014.07--2018.03 德国马克斯普朗克复杂系统物理研究所 博士后（洪堡****）
2018.03--2019.09 奥地利维也纳科技大学 博士后（迈特纳****）
2019.09-- 华东师范大学 青年研究员（紫江青年****）

个人简介
主要从事超快光学、阿秒物理、强场物理、原子分子光物理理论研究。
个人主页：http://concord.itp.tuwien.ac.at/~nih/

社会兼职
期刊审稿：Physical Review Letters; Physical Review A; Physical Review B; Journal of Physics B; Journal of Physics: Photonics; European Physical Journal D.


研究方向
人类对于越来越快的物理过程以及越来越短的时间尺度的追求是孜孜不倦的。早在19世纪，人们就发明了高速摄影技术，解决了当时关于“马在奔跑过程中是否会四脚离地”的争议。1980年代，飞秒（1fs = 10^-15s）激光开始发展，人们拍摄了化学反应中原子核的运动过程。目前脉冲更短的超快光源已经成熟，其脉冲长度已经缩短至阿秒（1as = 10^-18s）量级，从而可以观测电子的超快运动以及化学键的形成和断裂，是当前可以分辨的最快物理过程。强场超快光物理可以在前所未有的高场强、高时间分辨率情形下开展物性研究，是目前国内外蓬勃发展的学科之一。
我们利用超强超短脉冲、运用理论分析和数值模拟研究以下课题：
电离时间超快控制：观测并控制光电离、隧穿电离时刻。
光子动量传递过程：观测其光子动量如何在超快尺度上传递给电子。
化学反应相干控制：控制化学键的产生和断裂，从而控制化学反应过程及产物。
电子关联超快控制：调控超快过程中的电子关联作用。
你想知道如何在阿秒时间尺度观测、控制电子运动吗？加入华东师范大学精密光谱科学与技术国家重点实验室吴健教授团队倪宏程研究员课题组，我们一起追逐速度与激情！欢迎报考硕士、博士研究生，欢迎博士后访问****！
课题组成员



马永哲 硕士生 2019-- 毛晓丹 博士生 2020-- 宋姗姗 硕士生 2020--


开授课程


科研项目
Subcycle linear momentum transfer in tunneling ionization
Interaction of a strong laser pulse with matter transfers not only energy but also linear momentum of the photons. Recent experimental advances have made it possible to detect the small amount of linear momentum delivered to the photoelectrons in strong-field ionization of atoms. We present numerical simulations as well as an analytical description of the subcycle phase (or time) resolved momentum transfer to an atom accessible by an attoclock protocol (see Figure). We show that the light-field-induced momentum transfer is remarkably sensitive to properties of the ultrashort laser pulse such as its carrier-envelope phase and ellipticity. Moreover, we show that the subcycle-resolved linear momentum transfer can provide novel insights into the interplay between nonadiabatic and nondipole effects in strong-field ionization. This work paves the way towards the investigation of the so-far unexplored time-resolved nondipole nonadiabatic tunneling dynamics.
H. Ni, S. Brennecke, X. Gao, P.-L. He, S. Donsa, I. B?ezinová, F. He, J. Wu, M. Lein, X.-M. Tong, and J. Burgd?rfer, Phys. Rev. Lett. 125, 073202 (2020).
H. Ni, S. Donsa, and J. Burgd?rfer, J. Phys. Conf. Ser. 1412, 072024 (2020).
Polarization tagging of two-photon double ionization by elliptically polarized XUV pulses
We explore the influence of elliptical polarization on the (non)sequential two-photon double ionization of atomic helium with ultrashort extreme ultraviolet (XUV) light fields using time-dependent full ab initio simulations. The energy and angular distributions of photoelectrons are found to be strongly dependent on the ellipticity. The correlation minimum in the joint angular distribution becomes more prominently visible with increasing ellipticity (see Figure). In a pump-probe sequence of two subsequent XUV pulses with varying ellipticities, polarization tagging allows us to discriminate between sequential and nonsequential photoionization. This clear separation demonstrates the potential of elliptically polarized XUV fields for improved control of electronic emission processes.
S. Donsa, I. B?ezinová, H. Ni, J. Feist, and J. Burgd?rfer, Phys. Rev. A 99, 023413 (2019).
Deformation of atomic p_±orbitals in strong elliptically polarized laser fields: Ionization time drifts and spatial photoelectron separation
The dynamical orbital shape has so far eluded the studies of strong-field ionization. We theoretically investigate the deformation of atomic p_±orbitals driven by strong elliptically polarized (EP) laser fields and the role it plays in tunnel ionization. Our study reveals that different Stark effects induced by orthogonal components of the EP field give rise to subcycle rearrangement of the bound electron density, rendering the initial p₊and p_?orbitals deformed and polarized along distinctively tilted angles with respect to the polarization ellipse of the EP field (see Figure). As a consequence, the instantaneous tunneling rates change such that for few-cycle EP laser pulses the bound electron initially counter-rotating (co-rotating) with the electric field is most likely released before (after) the peak of the electric field. We demonstrate that with a sequential-pulse setup one can exploit this effect to spatially separate the photoelectrons detached from p₊and p_-orbitals, paving the way towards robust control of spin-resolved photoemission in laser-matter interactions.
K. Liu, H. Ni, K. Renziehausen, J.M. Rost, and I. Barth, Phys. Rev. Lett. 121, 203201 (2018).
Debate over Tunneling Time Delay Resolved by Backpropagation
We proposed a backpropagation method to temporally and spatially resolve the tunneling ionization dynamics. The backpropagation method involves a full quantum solution of the tunneling ionization followed by a classical propagation backwards in time in phase space to retrieve initial tunneling exit coordinates, including time and position (see Figure). In contrast to other methods, this method does not employ any assumptions or approximations to the quantum tunneling dynamics, while it is capable to obtain highly differential information regarding to the tunneling process. Thereby, we could also quantify the fraction of electrons that are ionized via tunneling, herewith we able to determine if ionization is in the tunneling regime in the first place. The backpropagation method also enables comparison of different definitions of and approximations to the tunnel exit on the same footing. A direct comparison including or not nonadiabatic tunneling effects reveals, that a positive tunneling time delay results if nonadiabaticity is not considered while a zero delay is obtained if nonadiabatic effects are taken full and consistent account of, thus resolving the long-standing debate over the existence of a finite tunneling delay.
H. Ni, U. Saalmann, and J.M. Rost, Phys. Rev. Lett. 117, 023002 (2016).
H. Ni, U. Saalmann, and J.M. Rost, Phys. Rev. A 97, 013426 (2018).
H. Ni, N. Eicke, C. Ruiz, J. Cai, F. Oppermann, N.I. Shvetsov-Shilovski, and L.W. Pi, Phys. Rev. A 98, 013411 (2018).
Double Photoionization of Helium Dimer
We studied the energy exchange between electrons in a helium dimer upon photon absorption. Results of numerical simulations for double photoionization are found to be in good agreement with recent experimental data for the angular distribution of the emitted electrons. Together with the temporal evolution of the two-electron probability distribution (see Figure) this provides direct evidence for the knockout mechanism. According to this mechanism, the photon energy, which is initially absorbed by an electron at one of the atoms in the dimer, is then shared between the electrons over distances of several Angstroms via an internal collisional process. Using a Hamiltonian reduction method we were also able to study the role of the interactions between different particles in the process.
H. Ni, C. Ruiz, R. D?rner, and A. Becker, Phys. Rev. A 88, 013407 (2013).
H. Ni and A. Becker, Phys. Rev. A 89, 033402 (2014).
Featured by Phys. Rev. A in their Kaleidoscope.
Delayed Resonant Two-Photon Ionization
The advancements in the understanding of the attosecond streaking camera technique opens the perspective to retrieve time-resolved information about the dynamics of electrons during transitions inside an atom or molecule. As a prototype example, we showed how the time delay in the resonant two-photon ionization as compared to the instantaneous transition from the ground state to the continuum in a nonresonant process (see Figure) can be retrieved from numerical results for attosecond streaking traces. We found that, the transition delay is linearly proportional to the duration of the ionizing pulse.
J. Su, H. Ni, A. Jaroń-Becker, and A. Becker, Phys. Rev. Lett. 113, 263002 (2014).
Finite-Range Attosecond Time Delays in Photoionization
Measurements of the photoelectron momentum as a function of the delay between an ionizing XUV and a superimposed infrared streaking pulse have recently revealed temporal offsets for the electron emission from different shells of an atom. We showed that results of related numerical simulations and classical analysis (see Figure) can be interpreted as due to the dynamics of the photoelectron in the Coulomb field of the parent ion and the streaking field. Thus, the time delay is accumulated over a finite range in space, which the photoelectron probes after its transition into the continuum until the streaking pulse ceases.
J. Su, H. Ni, A. Becker, and A. Jaroń-Becker, Phys. Rev. A 87, 033420 (2013).
J. Su, H. Ni, A. Becker, and A. Jaroń-Becker, J. Mod. Opt. 60, 1484 (2013).
J. Su, H. Ni, A. Becker, and A. Jaroń-Becker, Phys. Rev. A 88, 023413 (2013).
J. Su, H. Ni, A. Becker, and A. Jaroń-Becker, Chin. J. Phys. 52, 404 (2014).
J. Su, H. Ni, A. Becker, and A. Jaroń-Becker, Phys. Rev. A 89, 013404 (2014).
Selection Rules in Few-Photon Double Ionization
We analyzed the selection rules for the emission of two electrons from the helium atom following the absorption of a few photons from a laser field. The increase of the number of absorbed photons leads to alternating suppression and non-suppression of the back-to-back emission of the two electrons. The Figure shows a snapshot of the two-electron dynamics following single-photon (inner part of distribution) and two-photon double ionization (outer part of distribution).
H. Ni, S. Chen, C. Ruiz, and A. Becker, J. Phys. B 44, 175601 (2011).
Featured by J. Phys. B in their LabTalkand as the cover article.


学术成果
代表成果：
Theory of Subcycle Linear Momentum Transfer in Strong-Field Tunneling Ionization
Hongcheng Ni*, Simon Brennecke, Xiang Gao, Pei-Lun He*, Stefan Donsa, Iva B?ezinová, Feng He, Jian Wu, Manfred Lein, Xiao-Min Tong, and Joachim Burgd?rfer*
Physical Review Letters125, 073202 (2020). ? PDF? SuppMat
Tunneling ionization time resolved by backpropagation
Hongcheng Ni, Ulf Saalmann, and Jan-Michael Rost
Physical Review Letters117, 023002 (2016). ? PDF
Deformation of atomic p_±orbitals in strong elliptically polarized laser fields: Ionization time drifts and spatial photoelectron separation
Kunlong Liu, Hongcheng Ni*, Klaus Renziehausen, Jan-Michael Rost*, and Ingo Barth*
Physical Review Letters121, 203201 (2018). ? PDF? SuppMat
Time delays in two-photon ionization
Jing Su, Hongcheng Ni, Agnieszka Jaroń-Becker, and Andreas Becker
Physical Review Letters113, 263002 (2014). ? PDF
Tunneling exit characteristics from classical backpropagation of an ionized electron wave packet
Hongcheng Ni, Ulf Saalmann, and Jan-Michael Rost
Physical Review A97, 013426 (2018). ? PDF
Numerical simulations of single-photon double ionization of the helium dimer
Hongcheng Ni, Camilo Ruiz, Reinhard D?rner, and Andreas Becker
Physical Review A88, 013407 (2013). ? PDF


荣誉及奖励


招生信息














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