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Etude de lasers à cascade quantique par spectroscopie térahertz dans le domaine temporel

Abstract : This thesis presents a study of quantum cascade lasers using terahertz time-domain spectroscopy (TDS). TDS is an experimental technique which consists in detecting THz electric fields transmitted through a sample, offering the possibility of studying both static and dynamic effects in semiconductors. THz quantum cascade lasers are multiple quantum well structures that are considered as promising devices to fill the gap of far infrared emitters. In a first set of static experiments, we have measured the gain spectra of several samples and were able to identify the intersubband electronic transitions giving rise to gain and losses. We have also observed and explained the origin of a spectral gain narrowing in those lasers. In the dynamic experiments we switched the gain of a quantum cascade laser on to benefit from its non-stationary regime in order to amplify a THz wave. In this regime the gain of the laser is high and not clamped at the total losses above threshold. Finally, in a third set of dynamic experiments we measure the coherent THz emission of a laser using THz time-domain spectroscopy. The control of the phase of the laser was achieved by injection seeding it with a broadband THz pulse.
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Contributor : Dimitri Oustinov <>
Submitted on : Thursday, June 16, 2011 - 10:24:01 PM
Last modification on : Thursday, December 10, 2020 - 12:36:30 PM
Long-term archiving on: : Saturday, September 17, 2011 - 2:27:20 AM


  • HAL Id : tel-00601157, version 1


Dimitri Oustinov. Etude de lasers à cascade quantique par spectroscopie térahertz dans le domaine temporel. Physique Atomique [physics.atom-ph]. Université Pierre et Marie Curie - Paris VI, 2011. Français. ⟨tel-00601157⟩



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