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Experimental quantum optics using novel materials

Speaker: 
Tobias Vogl (Australian National University)
Date: 
Wed, 02/08/2017 - 11:00am to 12:00pm
Location: 
Physics Conference Room (S11-02-07)
Host: 
Professor Sow Chorng Haur
Event Type: 
Seminars

Abstract

Although most research on 2D materials is targeting electronic applications, recent advances have opened a new platform for single photon generation based on these novel materials. Single photons are a key resource for quantum optics and optical quantum information processing. The integration of scalable room temperature quantum emitters into photonic circuits remains to be a technical challenge.

First, I will explain the basics of quantum information processing, including quantum computing and quantum cryptography and outline how 2D materials can be used here. Next, I will present our latest experiment, where we utilized a defect center in hexagonal boron nitride (hBN) attached by Van der Waals force onto a multimode fiber as a single photon source. We performed an optical characterization of the source in terms of spectrum, state lifetime, power saturation and photostability. A special feature of our source is that it allows for easy switching between fiber-coupled and free space single photon generation modes. In order to prove the quantum nature of the emission we measure the second-order correlation function. For both fiber-coupled and free space emission, the second-order correlation function dips below 0.5 indicating operation in the single photon regime. The results so far demonstrate the feasibility of 2D material single photon sources for scalable photonic quantum information processing. Furthermore, I will show our new experiment of a high-speed and high purity single photon source.

About the speaker

Tobias Vogl studied physics and mathematics at the Ludwig-Maximilian-University of Munich (LMU) in Germany, where he received his B.Sc. and M.Sc. degree in 2014 and 2016, respectively. During his time in Harald Weinfurter's group at the LMU he first focussed on quantum hacking, demonstrating loopholes in free space quantum cryptography applications, while later he developed a mobile free space quantum key distribution experiment for short distance secure communication. Prior to the work on quantum cryptography he worked in Volodymyr Pervak's group on multilayer chirped coatings. Other research areas of interest include conventional cryptography and fundamentals of quantum mechanics.

In 2016 he joined Ping Koy Lam's group at the The Australian National University in Canberra, Australia as a PhD student. He is focusing on implementing 2D materials into quantum optics experiments, ranging from single photon generation to quantum optomechanics. He fiber-integrated a single photon source based on hexagonal boron nitride operating at room temperature. Current work includes building a near-ideal high-speed and high purity single photon source and theoretical modelling of electronical properties of 2D materials.

Tobias Vogl is a member of the Elite Network of Bavaria and the German Physical Society from which he was honoured for excellent performance in the field of physics. During his career he received multiple scholarships and fellowships.

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