Atomic, Molecular & Optical Physics (AMO) Projects
Modular Laser Health Monitoring System (Experiment)
E-mail: blaga@phys.ksu.edu
Small temperature changes inside a laboratory where lasers operate lead to small drifts in the pointing of the laser. This effect can be compensated using a beam pointing stabilization system, consisting of computer-controlled motorized mirror mounts and cameras. First, the computer stores a reference beam image in its memory, recording the position of the beam. At later times, new images are taken and the beam location is compared to the reference. If the location has changed – indicating a beam drift – the computer adjusts the mirror mount, moving the beam position back to its original position. The first implementation of this system, consisting on using one camera and one motorized mount has been developed successfully in 2021 by REU student Ms. Sara Sayer (see link below). For Summer 2022, we plan to finalize this project by adding a second camera and one additional motorized mount, additions that will complete the beam pointing stabilization system.
https://www.phys.ksu.edu/reu/2021/sayer.html
Computational ultrafast dynamics for molecules (Theory)
E-mail: lgreenman@phys.ksu.edu
The dynamics of molecules interacting with intense, ultrafast, or high-photon-energy laser fields pushes the frontier of complexity that can be described by current theories and computational techniques. However, it is precisely these regimes where we can learn new phenomena for molecules relevant to chemical reactivity and energy conversion. In this project, an REU student will explore new techniques for understanding molecular interactions on ultrafast timescales and complex dynamical processes.
Together, we will work with experimentalists at the James R. Macdonald Laboratory to understand complex processes by characterizing the potential energy of molecules at distorted geometries and in highly excited states. The student will learn to use state-of-the-art methods from the community of quantum chemistry, where quantum mechanics and applied mathematics are combined and applied to molecules. In the course of this project, we will use some of the most powerful supercomputers in the world including those at the National Energy Research Supercomputing Center (NERSC). Benefits include exposure to computer scripting in languages like Python, basic computer programming in Fortran or C++, and high-performance computational techniques.
Studying Ultrafast Molecular Dynamics in Pump-probe Experiments with Femtosecond Lasers (Experiment)
Daniel Rolles and Artem Rudenko
E-mail: rolles@phys.ksu.edu or rudenko@phys.ksu.edu
State-of-the-art femtosecond lasers can generate pulses with durations shorter than the time scales of fundamental molecular processes such as dissociation, rearrangement of molecular bonds, and vibrational motion. This can be exploited for creating “movies” of these processes in so-called pump-probe experiments. Here, the first (“pump”) laser pulse triggers the reaction of interest, and the second (“probe”) pulse, arriving after certain delay time, takes a snapshot of the molecular structure [1-3].
For the 2022 REU program, we offer a project focused on performing pump-probe experiments at the James R. Macdonald Laboratory using intense femtosecond laser pulses in the ultraviolet (UV) to near-infrared (NIR) spectral range. The main goal of these experiments will be to trace the time evolution of molecular reactions induced by either the UV or the NIR light pulse. Within the course of the project, the REU student will gain practical, hands-on experience working with ultrafast optics (in particular the characterization of femtosecond laser pulses), learn basics of laser interactions with atoms and molecules, get an introduction into electron and ion spectroscopy, and in the data acquisition and data analysis software for pump-probe experiments. The student will be co-mentored by Prof. Daniel Rolles and Prof. Artem Rudenko and work together with graduate students from the Rolles and Rudenko groups.
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S. Pathak et al., Nat. Chem. 12, 795-800 (2020).
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Y. Malakar et al., Phys. Chem. Chem. Phys. 21, 14090-14102 (2019).
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D. Rolles et al., Journal of Visualized Experiments 140, e57055 (2018).