Dresden 2011 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 29: Laserentwicklung: Nichtlineare Effekte 1

Q 29.10: Vortrag

Mittwoch, 16. März 2011, 12:45–13:00, SCH 251

Impact of injector length on interband cascade laser performance — •Robert Weih, Adam Bauer, Sven Höfling, Martin Kamp, Lukas Worschech, and Alfred Forchel — Technische Physik, University of Würzburg, Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems Am Hubland, D-97074 Würzburg, Germany

The interband cascade laser (ICL) is a novel type of unipolar semiconductor laser emitting in the mid-infrared wavelength range. Although the laser operation is driven by interband transitions between electron states and hole states, only electrons are injected. While travelling through a cascaded active region, these electrons generate multiple photons making the ICL a hybrid laser, combining advantages of diode lasers and QCLs. Whereas bipolar diode lasers utilize also interband transition, but within a pn-junction, QCLs are unipolar devices and thoroughly based on intersubband transitions between electron states.

In this work ICLs were grown by MBE and investigated via temperature dependent electro-optical measurements. It was found that shortening the chirped superlattice injector regions used for resonant tunnel injection of electrons into the type-II "W" active regions improves the laser performance significantly. Stepwise reduction of the injector length from 74nm to 49nm led to close to linear dependence between pulsed maximum operation temperatures and injector length, while threshold current figures could be reduced monotonically. Devices incorporating the optimized shortened injector layout reach operation temperatures exceeding 335K (pulsed) and 273K (cw).