Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 46: Quantum dots and wires: Optical properties III
HL 46.1: Vortrag
Donnerstag, 15. März 2018, 15:00–15:15, A 151
Ultrasensitive, high spectral resolution photocurrent spectroscopy of single QDs — •Sebastian Krehs1, Alex Widhalm1, Amlan Mukherjee1,2, Björn Jonas1, Nand Lal Sharma1, Peter Kölling2, Andreas Thiede2, Jens Förstner2, Dirk Reuter1, and Artur Zrenner1 — 1Physics Department, University of Paderborn — 2Department of Electrical Engineering, University of Paderborn, Paderborn 33098, Germany
Single InGaAs QDs embedded in electric field tunable structures allow for the realization of new coherent optoelectronic functionalities [1, 2]. In optical experiments on single QD photodiodes the exciton ground state transition appears as a two-level system with an almost lifetime limited linewidth of a few µeV. The measurement of the ground state occupancy can be performed quantitatively via photocurrent (PC) detection. Refinements of this method enabled us to improve its sensitivity down to the fA range. Resonant cw laser spectroscopy with high spectral resolution allows us to investigate the linewidth of QDs at very low excitation powers and at exceptionally low tunneling rates. Combined with PC detection we are able to demonstrate exciton linewidth down to 1.62 µeV. This result is close to the Fourier transform limit of the QD linewidth [3]. Ultrasensitive PC measurements at extremely low tunneling rates may be used in the future to perform the frequency stabilization of single photon emitters.
Ref:[1] A. Zrenner et al., Nature 418, 612 (2002). [2] S. de Vasconcellos et al., Nature Photonics 4, 545 (2010). [3] A.V. Kuhlmann et al. Nature Physics 9, 570-575 (2013).