Zifei Zhang

Curriculum Vitae

Research Experience

• 02/2021-12/2021
  Internship, Nano & Quantum Optics
  Worked with M-profile optical fiber.
  Coupled IR-laser into the fiber and observed optical modes with CCD.
• 02/2022-05/2023
  Research Lab, Nano & Quantum Optics
  Worked with Transition Metal Dichalcogenides (TMDs).
  Operated Confocal-Fluorescence Microscope and Scattering Scanning Near-field Optical Microscope (Neaspec IR-neaSCOPE).
  Investigated second harmonic generation (SHG) in monolayer WSe22 and WS22.
  Analyzed Photoluminescence (PL) and Raman spectra.
• 06/2023-04/2024
  Master Thesis, Nano & Quantum Optics
  Worked with Kelvin Probe Force Microscope (KPFM, JPK NanoWizard).
  Studied Si nanoparticle arrays and their optical properties.
  Investigated hybrid systems: TMDs-monolayer/Si-nanoparticles.
  Analyzed Photoluminescence (PL), Raman spectra using Python and Matlab, and processed KPFM images.

Education

• 10/2020-06 2024
  MSc. Photonics at Friedrich-Schiller-Universität Jena
  Relevant courses: Applied and Physical Optics, Foundation of Precision Mechanism Design, Analog and Digital Electronics, Principle and Design of Optoelectronics Instrument.
• 09/2016-07/2020
  BSc. Measurement Control Technology and Instrument at Beijing Institute of Technology (China)
  Thesis title: Colour characterisation of display devices - Colour space transformation using machine learning training models.

PhD Project

This project employs time-resolved second-harmonic generation (SHG) spectroscopy to investigate light-driven transient changes in charge density distributions at photo-polarizable interfaces and membranes.

The study focuses on multiple material systems: photosensitive carbon nanomembranes and van-der-Waals heterostructures of transition metal dichalcogenides are examined to unravel switching dynamics and valley-selective polarizability effects, while rare earth/transition metal-doped oxide glasses are explored for their photo-poling behavior. Additionally, molecularly thin Langmuir layers serve as platforms to probe orientation-dependent charge dynamics of supramolecular aggregates, and synthetic lipid membranes with light-responsive ion transport properties are analyzed for their electrical rectification capabilities.

Collaborations with PhInt research groups enhance the project’s scope: research groups of Prof. Turchanin and Prof. Presselt can provide functionalized nanomembranes and Langmuir-Blodgett layers, Prof. Schröder’s group contributes light-tunable lipid membranes, and Prof. Wondraczek’s group can offer expertise in poling dynamics of doped glasses.  

Experimental methods center on ultrafast pump-probe SHG spectroscopy, enabling picosecond-resolution tracking of nonlinear polarizability changes. Key parameters—excitation wavelength, intensity, polarization, and SHG fundamental wavelength—are systematically varied to dissect dynamic contributions. For further development, a novel polarization-resolved back-focal plane SHG imaging technique can be proposed, extending prior applications in single-molecule studies to map orientation shifts in supramolecular membrane aggregates.

By correlating SHG signal variations with transient charge redistribution, the project aims to advance understanding of light-matter interactions in various materials, with potential implications for optoelectronics, photonics, and bioinspired membrane technologies.