Internship Project
Physics

Optical Limiting of Macromolecules: Theory and Experiments

Institution
Humboldt-Universität zu Berlin,
Department of Physics
Subject Area
Physical chemistry, spectroscopy
Availability
05 May – 25 July
19 May – 08 August
02 June – 22 August
16 June – 05 September
 
Internship Modality:
On-site internship in Berlin

Applications for 2025 are open from November 11 to December 20, 2024.
Project Supervisor(s)
Prof. Dr. Zsuzsanna Heiner, Prof. Dr. Caterina Cocchi
Academic Level
Advanced undergraduate students (from third year) 
Master's students 
Ph.D. students 
Language
English
Project Type
Academic Research
Project Content
Optical limiting is an intriguing phenomenon exhibited by several macrocyclic molecules, including popular compounds like phthalocyanines and porphyrins. While known for decades and exploited in several technological applications, particularly concerning the protection of human eyes from intense laser irradiation, the fundamental mechanisms ruling this phenomenon are yet to be fully understood.

In this project, combining experimental and theoretical research, we will investigate optical limiting in (biological) macromolecules, focusing on the primary steps leading to these processes. To do so, we will adopt state-of-the-art laser spectroscopy methods and ab initio calculations based on time-dependent density functional theory to parallelly disclose and analyze phenomena like excited-state absorption, reverse saturable absorption, and multiphoton absorption that mostly contribute to the emergence of optical limiting in the investigated compounds.

To analyze both the theoretical and experimental aspects, we offer two internship positions, each of which is dedicated to one part of the project.
Tasks for Interns
Position 1 (experiments)
  • Learn to align the small optical setup, master the use of the necessary table-top devices, and become proficient with the measurement software. 
  • Set up, align, and run femtosecond z-scan measurements
  • Preprocess and analyze the results and compare them with the theoretical data

Position 2 (theory)
  • Familiarize yourself with the code adopted for the calculations (octopus code) and the computational environment
  • Set up and run the calculations
  • Analyze the results and compare them with the experimental data
Academic Level
Advanced undergraduate students (from third year) 
Master's students 
Ph.D. students 
Requirements
Position 1 (experiments)
  • Practical experience in at least one of the following fields: ultrafast optics, nonlinear optics, laser spectroscopy, building or aligning small optical setups
  • Basic knowledge of optics, molecular physics, and nonlinear optics
  • Willingness to work in a laser laboratory
  • Basic experience using home-written MATLAB codes for data analysis

Position 2 (theory)
  • Very good knowledge of quantum mechanics
  • Basic knowledge of atomic and molecular physics
  • Familiarity with computational tools for scientific computing
  • Experience with ab initio calculations (density-functional theory, time-dependent density-functional theory, ab initio molecular dynamics) - optional
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For more information on the Humboldt Internship Program or the project, please contact the program coordinator.