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Q: Fachverband Quantenoptik und Photonik

Q 53: Nano-Optics II

Q 53.7: Vortrag

Donnerstag, 17. März 2022, 15:30–15:45, Q-H11

Direct Measurement of Emission Probabilities in Single Photon Emitters — •Pablo Tieben^{1, 2} and Andreas W. Schell^{1, 2} — ¹Physikalisch-Technische Bundesanstalt, Braunschweig, Germany — ²Gottfried Wilhelm Leibniz Universität, Hannover, Germany

Single photon sources are an essential part in the development of a number of quantum technologies. Understanding the intrinsic properties of new sources of single photons is paramount for their successful application. One of the key properties, among others, is their saturation behavior in terms of the ratio of the number of excitation photons to the number of emitted photons. Especially for photoactive defect centers in semiconductors, the existence of intermediate dark states has been shown, which leads to a shelving effect at high excitation powers. To circumvent this limitation of the photon yield, a repumping from these long lived states can be implemented via two-color excitation, where the second wavelength is matched to the transition energy between the intermediate and the excited state. We report on a measurement technique to directly determine the excitation probability as a function of the pulse intensity by using a tunable, strongly fluctuating, pulsed source of laser light and performing time correlated measurements between the pulse intensity and the photon count events in a synchronized time basis. Furthermore, we apply this scheme to two-color excitation measurements of single photon emitters in hexagonal boron nitride (hBN) to simultaneously retrieve saturation functions over the two dimensional parameter space of wavelength dependent excitation power.