Non-classical photon correlation in a two-dimensional photonic lattice

Abstract

Quantum interference and quantum correlation, as two main features of quantum optics, play an essential role in quantum information applications, such as multi-particle quantum walk and boson sampling. While many experimental demonstrations have been done in one-dimensional waveguide arrays, it remains unexplored in higher dimensions due to tight requirement of manipulating and detecting photons in large-scale. Here, we experimentally observe non-classical correlation of two identical photons in a fully coupled two-dimensional structure, i.e. photonic lattice manufactured by three-dimensional femtosecond laser writing. Photon interference consists of 36 Hong-Ou-Mandel interference and 9 bunching. The overlap between measured and simulated distribution is up to 0.890 ± 0.001. Clear photon correlation is observed in the two-dimensional photonic lattice. Combining with controllably engineered disorder, our results open new perspectives towards large-scale implementation of quantum simulation on integrated photonic chips.

Experimental two-dimensional quantum walk on a photonic chip

“…However, these experimental implementations reveal a very evident limitation: The realized QW is normally of only one dimension, and the evolving scale of QWs remains very small. A simple demonstration of 1D QW could not suffice the ever-growing demand for further speedup of certain quantum algorithms or the simulation of quantum systems of a much higher complexity ( 18 , 19 ). In the spatial search algorithm, a QW outperforms its classical counterparts only when the dimension is higher than one ( 20 ); in the simulation of graphene, photosynthesis, or neural network systems, these complex networks always intuitively have high dimensions.…”

FeynmanPAQS: A Graphical Interface Program for Photonic Analog Quantum Computing

“…The genuine quantum interference (also known as Hong-Ou-Mandel (HOM) effect 58 ), which cannot be classically simulated, gives rise to non-classical quantum correlations 59 . With two particles populating in a two dimensional lattice, the corresponding state space can be easily extended to a greater dimension 60 . Such high dimensional graphs demonstrate quantum speedup for continuous-time search algorithm 54 .…”

Mapping and measuring large-scale photonic correlation with single-photon imaging

“…For example, Hong-Ou-Mandel (HOM) interference can reveal the nonclassical bunching properties of photons [1]. These correlation characteristics are crucial in quantum computing [2][3][4][5], quantum simulation [6][7][8][9] and quantum communication [10][11][12][13].…”

“…In theory, especially in the field of quantum computing, if we manage to send enough entangled photons into plenty of modes and operate their superposition states simultaneously, we would be able to obtain sufficiently large quantum state space that may enable a higher computational power than classical computers. In practice, it may still be acceptable to place single photon detector behind each spatial mode for comparably small systems [9,[14][15][16]. However, it will become both technically challenging and economically unfeasible to address thousands of modes simultaneously with single photon detectors, and therefore become a decisive bottleneck preventing from detecting state spaces large enough for real quantum applications.…”