Combined dynamic Electron Microscope and optical microscope: An ideal tool to study optical properties of quantum materials

Speaker: Samuel Sonderegger, Ph.D., Attolight AG, Lausanne, Switzerland
Date & Time: Wed, Sep 27, 2017 at 2:00 PM
Location: AMPEL 311
Local Contact: Alan Maigne
Intended Audience:

Spectroscopic information may be acquired using an electron beam in a modern electron microscope (EM), exploiting the cathodoluminescence (CL) signal. CL offers several advantages over the usual optical spectroscopy. The multimode imaging capabilities of an EM enable the correlation of optical properties with morphology and structure at the sub-nanometer scale under beam or photon excitation. In addition, the large energy of the electrons allows the excitation of wide-bandgap materials. We will present an ultrafast dynamic EM combined with an optical microscope in a unique collinear arrangement: this system is a time-resolved spectroscopic platform that allows to collect time-resolved cathodoluminescence down to the picosecond time range and to carry out advanced pump probe experiments. In addition, it is equipped with a low temperature cryogenic stage allowing for experiments below 10K. Electron pulses are obtained through the photoelectric effect by focussing laser pulses on the field emitter tip. We will give an overview of applications.

Samuel studied at EPFL (Swiss Federal Institute of Technology, Lausanne) and Ecole Normale Supérieure de Lyon (France) and obtained a MS of Physics from EPFL. His master thesis on the optical properties of semiconductors was conducted at the Ioffe Physico-Technical Institute (Russia). During his PhD at EPFL, he further developed an ultrafast cathodoluminescence technology and used this technique to advance the understanding of optical properties of nitride based semiconductors. The technique is uniquely based on the photoelectric effect and makes use of a pulsed laser to create electron pulses. Samuel decided to jump into the entrepreneurial world after his PhD thesis and co-founded Attolight with Jean Berney. Attolight, a spin-off from EPFL’s
Laboratory of Quantum Optoelectronics, builds and commercializes electron microscopes based on the ultrafast cathodoluminescence technology. Since the creation of Attolight, Samuel has headed the business development of the company proposing custom ultrafast CL technology solutions to academic and industrial users.