Tomography of the Temporal-Spectral State of Subnatural-Linewidth Single Photons from Atomic Ensembles
Ce Yang, Zhenjie Gu, Peng Chen, Zhongzhong Qin, J. F. Chen, Weiping Zhang · Physical Review Applied · 2018
Encoding information in the temporal-spectral mode of single photons attracts growing attention in the community of photonic quantum technology. The temporal mode, with ultralong coherence time, of single photons from atomic ensembles is easy to control, but the conventional photon-counting technique provides only the amplitude of the temporal-mode function. This study develops a cavity-free homodyne detection scheme to characterize the $c\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}m\phantom{\rule{0}{0ex}}p\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}e$ temporal state of narrow-band single photons, paving the way to exploit the temporal-spectral degree of freedom in photonic quantum information processing.