On Monday (12/19/22) at 12:00 pm c.t. the next meeting of our Physics Colloquium will take place.
The speaker is Dr. Nahan Jukam (RUB) with his inaugural lecture on the topic: "Investigation of Quantum Cascade Lasers Using Time Domain Spectroscopy ".
Due to their small size and potential for mass fabrication, quantum cascade lasers are promising sources of terahertz (THz) radiation. In contrast to interband laser diodes, the laser transition in quantum cascade lasers takes place between intersubband levels. By careful control of the lengths and composition of quantum wells and barriers during molecular beam epitaxy growth, the injection rates into intersubband levels and intersubband lifetimes can be designed to achieve population inversion.
In this talk THz time-domain spectroscopy is used to measure the stimulated emission resulting from the injection of THz probe pulses into quantum cascade lasers. This allows the alignment of the intersubband levels to be investigated both above and below threshold and gives unique insights into gain mechanisms. By operating the quantum cascade lasers in a transient regime, the gain above threshold is enhanced which results in large amplification of the THz probe pulses. Injecting a second THz probe pulse into the quantum cascade laser enables two-dimensional spectroscopy to be per-formed and the gain recovery and spatial hole burning response of the quantum cascade lasers to be investigated.
Abstract lecture Dr. Nathan Jukam
The introduction will be given by Prof. Dr. Ilya Eremin.
The faculty cordially invites all interested parties. The event will take place in lecture hall HNC 10 and hybrid via Zoom. Before the colloquium we offer coffee and cookies.
This link will take you to the Zoom event (Meeting-ID: 632 5520 9938, password: 526977). All dates of the Physics Colloquium can be found here.