Recent advances in laser technology have provided us with ultra-intense laser sources with electric field strengths that can match and even exceed the internal forces that hold atoms together. These sources allow us to selectively remove electrons within sharp windows of time and then control their motion using the waveform of the light, driving them back to collide with their parent ion to emit high-frequency harmonics or obtain valuable electron-diffraction patterns .
These processes occur in a quantum-mechanical setting where electrons must be described as waves, but the high intensity of the light allows for a quasi-classical description in terms of trajectories that are analogous to the use of ray optics to describe light waves. Unfortunately, this trajectory formalism breaks down at places, known as caustics, where the trajectories accumulate and the matter wave has its highest amplitudes. Recent work has shown how to handle this breakdown , using analytical tools to find the ‘true’ location of the electron-trajectory caustic, opening many questions about how these caustics should be described and how they can be used to power novel applications.
In this project, you will explore this new frontier and expand it into new regimes. You will examine the behaviour of the electron-trajectory caustic for a variety of driving light fields, and use the resulting insights to design schemes to optimize high-harmonic sources. You will benchmark and solidify the existing analytical and numerical formalism to provide a solid and reliable tool for calculation, and use this baseline to probe more complex driving fields. As the project progresses, we will turn to higher-order analogues of caustics, known as ‘catastrophes’, to both model them in detail and use them to optimize strong-field processes.
The activities involved in the project will include:
· Theoretical analysis, using analytical and numerical methods, of high-harmonic generation and other strong-field processes.
· Development and optimization of software for numerical calculations.
· Collaboration with experimental groups to propose new experiments and analyze existing data.
· Attendance of conferences, workshops and summer schools.
Prospective candidates will be judged according to how well they meet the following criteria:
· A first -class honours degree to second class honours upper division (2.1) in Engineering, Physics or Chemistry
· Excellent English written and spoken communication skills see https://www.kcl.ac.uk/study/postgraduate/apply/entry-requirements/english-language.aspx
· A background in quantum mechanics or optics
· Fluency with analytical methods of theoretical physics and ability to apply mathematical skills to analyze and solve problems
· Ability to formulate and test hypotheses and to generate and analyze numerical data
· Ability to effectively communicate research findings
The following skills are desirable but not essential:
· An interdisciplinary degree, or experience outside of main degree topic
· Experience in working in a research environment
· Basic knowledge of strong-field physics and attosecond science, including high-harmonic generation and related processes
· Experience with asymptotic methods for evaluation of integrals, including saddle-point and steepest-descent methods
· Knowledge of Wolfram Mathematica or other computer algebra systems
· Ability to program in one or more programming language, such as Wolfram Language, python, Julia, C++, etc.
· A background in complex analysis and related topics.
Start date: October 2022
For enquiries please contact: Dr Emilio Pisanty, [Email Address Removed]
For full information on how to apply: https://apply.kcl.ac.uk
The Physics department at King’s College London supports Diversity and Equality and we invite all eligible candidates to apply.
The Physics department at King’s College London was awarded the Silver Swan medal and Juno Champion award from IOP: