Design of mid-infrared entangled photon sources using lithium niobate

Abstract

The mid-infrared (MIR) band entangled photon source is vital for the next generation of quantum communication, quantum imaging, and quantum sensing. However, the current entangled states are mainly prepared in the visible or near-infrared bands. It is still lacking high-quality entangled photon sources in the MIR band. In this work, we optimize the poling sequence of lithium niobate to prepare two kinds of typical entangled states, the Hermit–Gaussian state and the comb-like entangled state at 3.2 µm. We have also calculated the photon pair rates and estimated the effect of fabrication resolution in the schemes. Our approach will provide entangled photon sources with excellent performance for the study of quantum information in the MIR band.

Quantum entanglement and interference at 3 μm

“…Similar to its partner in NIR band, quantum light sources in the MIR region can also be generated by using spontaneously parametric processes (SPDCs) in a nonlinear crystal (26)(27)(28). Recently, there are some works about the generation and detection of MIR photon sources theoretically and experimentally (29)(30)(31), and the demonstration of quantum interference and entanglement (32). However, because of the limitations of optical devices and detector performance, research related to the generation of entanglement and photon interference in MIR band has progressed slowly in the past years.…”

Controllable transitions among phase-matching conditions in a single nonlinear crystal

“…The biphotons can be further engineered to prepare a heralded single-photon source or entangled photon source. The SPDC process can be engineered in different degrees of freedom, such as space, time, frequency, polarization, and phase [5,6] .…”

“…Another important feature of the Type-II matching condition is that the joint spectral distribution of biphotons can be engineered according to the group velocity differences [17] . As a result, one can prepare photon pair sources with engineerable frequency correlation [5,6,18] .…”

Mid-infrared spectrally-pure single-photon states generation from 22 nonlinear optical crystals

“…On the experimental side, PPLN [14][15][16], GaP [17], and silicon waveguide [18] have been investigated to prepare single-photon source; PPLN [19] has been studied for entangled photon source generation. On the theory side, PPLN [20], PPKN [21], PMN-0.38PT [22], etc have been investigated for single-photon source [23][24][25][26][27]; p-doped semiconductor [28] has been studied for entangled photon source. In addition, some studies explored single-photon detection by superconducting nanowire single-photon detector (SNSPD) [29][30][31] or by silicon avalanche photodiode (SAPD) in an up-conversion configuration [14,32].…”