Dresden 2020 – wissenschaftliches Programm

Die DPG-Frühjahrstagung in Dresden musste abgesagt werden! Lesen Sie mehr ...

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

HL: Fachverband Halbleiterphysik

HL 51: Semiconductor lasers I

HL 51.4: Vortrag

Mittwoch, 18. März 2020, 15:45–16:00, POT 51

Miniaturized lasers for picosecond ultrasonics — •Michal Kobecki — Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund, Germany

There is a great desire to extend ultrasonic techniques for imaging and characterization of nanoobjects. This may be achieved by picosecond ultrasonics, where using ultrafast lasers it is possible to generate and detect acoustic wave with the frequencies up to terahertz and wavelength down to nanometers. In our work we present the picosecond ultrasonics setup based on miniaturezed mode-locked semiconductor lasers, which are appropriate to obtain necessary power, pulse duration and repetition rate.

Project was focused on generation and detection of the strain pulses in thin metal films (Al,Pt,Cr,Au) deposited on GaAs substrates. The used mode locked laser diode (MLLD) based on AlGaInAs/InP quantum-well active media was manufactured at Glasgow University. Invastigated device emits 1-ps duration laser pulses with repetition rate of 20 GHz and average power of 50mW at 930nm wavelength.In experiments we have used standard pump-probe scheme. Detected signal reflects an ultra-short strain pulse generated in a film and its echo arriving back to the surface. Observed signals are in perfect agreement with the data obtained by means of conventional set-ups, which gives motivation for further development in the field and pursuing more ambitious goals.