TY - BOOK

T1 - Towards a room temperature single photon source based on atomic vapour

AU - Zugenmaier, Michael Viktor Alban

PY - 2018

Y1 - 2018

N2 - Efficient quantum communication over long distances requires quantum repeaters along the communication line. Quantum repeaters based on room temperature systems offer advantages due to their scalability. However, atomic motion has until now prevented these systems to reach long lifetimes of heralded single collective excitations in room temperature systems. We study the characteristics of vapour cells with anti-relaxation coating which allows for long lifetimes. We demonstrate efficient heralding and readout of single collective excitations created in warm caesium vapour. Using the concept of motional averaging, we can achieve a lifetime of the collective excitation of 0.27 0.04 ms, two orders of magnitude longer than previous warm vapour experiments on the single photon level. We verify the non-classicality of the correlations between heralding and readout fields by a significant violation of the Cauchy-Schwarz inequality with R = (1.4 0.1) > 1. The spectral and temporal analysis of the noise contributions that contaminate the single photon readout allows us to identify leakage of excitation light and intrinsic four-wave mixing as two main contributions. In a proof-of-principle experiment we confirm an experimental solution to suppress the four-wave mixing noise. We discuss possibilities to identify and possibly eliminate the remaining noise sources and thus with an improved setup to advance towards the applicability as an on-demand single photon source.

AB - Efficient quantum communication over long distances requires quantum repeaters along the communication line. Quantum repeaters based on room temperature systems offer advantages due to their scalability. However, atomic motion has until now prevented these systems to reach long lifetimes of heralded single collective excitations in room temperature systems. We study the characteristics of vapour cells with anti-relaxation coating which allows for long lifetimes. We demonstrate efficient heralding and readout of single collective excitations created in warm caesium vapour. Using the concept of motional averaging, we can achieve a lifetime of the collective excitation of 0.27 0.04 ms, two orders of magnitude longer than previous warm vapour experiments on the single photon level. We verify the non-classicality of the correlations between heralding and readout fields by a significant violation of the Cauchy-Schwarz inequality with R = (1.4 0.1) > 1. The spectral and temporal analysis of the noise contributions that contaminate the single photon readout allows us to identify leakage of excitation light and intrinsic four-wave mixing as two main contributions. In a proof-of-principle experiment we confirm an experimental solution to suppress the four-wave mixing noise. We discuss possibilities to identify and possibly eliminate the remaining noise sources and thus with an improved setup to advance towards the applicability as an on-demand single photon source.

UR - https://soeg.kb.dk/permalink/45KBDK_KGL/1pioq0f/alma99122348884805763

M3 - Ph.D. thesis

BT - Towards a room temperature single photon source based on atomic vapour

PB - The Niels Bohr Institute, Faculty of Science, University of Copenhagen

ER -