Synthetic five-wave mixing in an integrated microcavity for visible-telecom entanglement generation

Abstract

Nonlinear optics processes lie at the heart of photonics and quantum optics for their indispensable role in light sources and information processing. During the past decades, the three- and four-wave mixing (χ(2) and χ(3)) effects have been extensively studied, especially in the micro-/nano-structures by which the photon-photon interaction strength is greatly enhanced. So far, the high-order nonlinearity beyond the χ(3) has rarely been studied in dielectric materials due to their weak intrinsic nonlinear susceptibility, even in high-quality microcavities. Here, an effective five-wave mixing process (χ(4)) is synthesized by incorporating χ(2) and χ(3) processes in a single microcavity. The coherence of the synthetic χ(4) is verified by generating time-energy entangled visible-telecom photon pairs, which requires only one drive laser at the telecom waveband. The photon-pair generation rate from the synthetic process shows an estimated enhancement factor over 500 times upon intrinsic five-wave mixing. Our work demonstrates a universal approach of nonlinear synthesis via photonic structure engineering at the mesoscopic scale rather than material engineering, and thus opens a new avenue for realizing high-order optical nonlinearities and exploring functional photonic devices.

Optical manipulation and conversion in whispering gallery mode resonators with pump depletion

“…These results yield new insight into the dynamics of nonlinear optical interactions in WGMRs, and provide an alternative method to manipulate the signal light in integrated photonic circuits and to convert the signal light into the idler light with amplified conversion efficiencies. Our work could also be extended to the cascaded Pockels nonlinear process [60] and five-wave mixing [61] for further investigation.…”

Extraordinary Five-Wave Mixing in a Zinc Oxide Microwire on a Au Film

“…, where E 0 is the mode distribution of 5WM, E 1 and E 2 denote the local fields of the excitations, and χ (4) is the fourth-order nonlinear susceptibility. By simplifying the Au film ZnO MW as a bulk crystal sheet, we can estimate the effective component χ (4) to be 3.5 nm 3 /V 3 , which is approximately several orders larger than those of many common nonlinear materials 30 (see section S6 of the Supporting Information).…”

“…, where E 0 is the mode distribution of 5WM, E 1 and E 2 denote the local fields of the excitations, and χ (4) is the fourth-order nonlinear susceptibility. By simplifying the Au film ZnO MW as a bulk crystal sheet, we can estimate the effective component χ (4) to be 3.5 nm 3 /V 3 , which is approximately several orders larger than those of many common nonlinear materials 30 (see section S6 of the Supporting Information). This formula also indicates that there are many factors that could influence 5WM, such as the local field distribution and their overlapping (phase matching), in addition to the excitation or emission enhancement discussed above.…”

“…First, two excitation plane waves were input vertically onto the ZnO MW, with their polarizations parallel to the c-axis. 5WM polarization P (5WM) is obtained by the local field at two excitations multiplied by the fourth-order nonlinear susceptibility of ZnO MW via the equation P (5WM) = ε 0 χ (4) :E 1 3 E 2 *. To simplify the calculations, we considered only the χ ccccc (4) component.…”

“…Wave mixing processes lie at the heart of a large range of applications, like parametric amplification, frequency conversion, generation of entangled photon pairs, , and spectroscopy . Because the n th-order nonlinear susceptibility is usually inversely proportion to the n – 1 power of the inner electric field inside the atom, the efficiency of the n > 2 process is very low, decaying exponentially with order.…”