Publications by Thomas Hird


Raman quantum memory with built-in suppression of four-wave-mixing noise

Physical Review A American Physical Society 100 (2019) 033801

Thomas, T Hird, J Munns, B Brecht, D Saunders, J Nunn, IA Walmsley, PM Ledingham

Quantum memories are essential for large-scale quantum information networks. Along with high efficiency, storage lifetime, and optical bandwidth, it is critical that the memory adds negligible noise to the recalled signal. A common source of noise in optical quantum memories is spontaneous four-wave mixing. We develop and implement a technically simple scheme to suppress this noise mechanism by means of quantum interference. Using this scheme with a Raman memory in warm atomic vapor, we demonstrate over an order of magnitude improvement in noise performance. Furthermore we demonstrate a method to quantify the remaining noise contributions and present a route to enable further noise suppression. Our scheme opens the way to quantum demonstrations using a broadband memory, significantly advancing the search for scalable quantum photonic networks.


Engineering a noiseless and broadband Raman quantum memory for temporal mode manipulation

Frontiers in Optics / Laser Science Part F114-FIO 2018 (2018)

TM Hird, S THOMAS, J MUNNS, J Nunn, O Arjona, S Gao, B Brecht, PM Ledingham, IAN WALMSLEY

© 2018 The Author(s). The Raman quantum memory can manipulate temporal modes of light - a promising high-dimensional basis for quantum information processing. We demonstrate both temporal mode manipulation and a novel suppression scheme for four-wave mixing noise.