23. Apr. 2015, 16:15 Uhr, Gebäude NW1, Raum H3
Neuartige Lichtquellen und photonische Bauelemente auf der Basis nanostrukturierter Halbleitermaterialien
Prof. Dr. J. P. Reithmaier, Universität Kassel
Vorgetragen wird in deutscher Sprache!
Novel Light Sources and Photonic Devices Based on Nanostructured Materials
The control of geometric dimensions of solids on the nanoscale opens new degrees of freedom to tailor electronic, optical and structural material properties for specific device functionalities. The talk will give a brief introduction to the growth of self-assembled III-V quantum dot (QD) structures. The impact of different properties of nanostructured materials on specific or novel device features will be discussed in several examples.
Recent progress in InP based QD growth allows the realization of more round-shaped geometries with strongly increased densities and reduced height fluctuations resulting in a tripling of the optical modal gain. These new properties allow the realization of 1.5 µm QD lasers with improved or novel device features, e.g., record-high direct digital modulation of 23 GBit/s, or narrow linewidth lasers with one order of magnitude reduced linewidths.
Quite different properties are needed for single photon emitters in the 1.5 µm regime. For this purpose the density of QDs have to be reduced by about two orders of magnitude and the light emission enhanced by Bragg reflectors, which allow to address single isolated dots. Optical spectroscopy proves true single-photon emission with high efficiency and a fine structure splitting in the range of the spectroscopic resolution.
To overcome the continuously increasing power consumption in information processing and transmission, optical technologies have to penetrate more and more near or onto the chip level. Key devices for networking systems are optical switches. By utilizing the non-linear light-matter interaction in InP based strongly coupled photonic crystal microcavities, low-power consuming highly integrated all-optical gates were realized with 60 fJ/bit switching energy and switching times down to 6.5 ps.
Finally a new pathway for the realization of optically active silicon will be briefly discussed, which utilizes nanostructure technologies to integrate monolithically III-V compounds in silicon and which can revolutionize in future the integration of optoelectronics on a new common silicon based platform.