Author: media.ccc.de - Bewertung: 1x - Views:20
https://media.ccc.de/v/gpn24-476-ultrafast-lasers-101-a-photonic-adventure-for-molecular-dynamics-enthusiasts
I'll cover the fundamentals of laser operation, including gain, population inversion and how you convince a bunch of excited atoms to all emit light in sync instead of doing their own thing.
We then explore how femtosecond pulses are produced in practice.
I'll explain some simple methods for shaping, tweaking, and measuring those pulses.
As a practical example, I will walk you through the velocity map imaging (VMI) setup I work with to show what can be done with this equipment, watching molecules fall apart, like a molecular stroboscope.
I work in a research group¹ doing "Ultrafast Dynamics inside He Nanodroplets".
I'd like to share some of the fascinating concepts, from my perspective doing real time data analysis for the research group.
„In order to measure an event in time, you must use a shorter one...“ ~ Rick Trebino
This is why we are interested in pulses of that regime, molecular dynamics operate exactly at that timescale.
But when one works with such short pulses, not only aligning the setup becomes a real pain, but also non-linear effects take over in ways you wouldn't expect from a classic optics viewpoint. Comparable to RF magic in electronics, you wouldn't expect when you look at low frequencies.
The goal is to develop an intuitive understanding of how the knowledge fits together and what those techniques enable us to observe.
I will not go deep into the details, because this topic is extremely complex and even the master's course at my university about "Ultrafast laser physics" is an overview of the topic. So this is going to be "an overview of an overview", a 101.
[1] Femtosecond Dynamics, TU Graz ( https://www.tugraz.at/en/institutes/iep/research/femtosecond-dynamics )
Sally
https://cfp.gulas.ch/gpn24/talk/JL7QUB/
#gpn24 #Science
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