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An on‐chip dual‐mode all‐optical multifunctional logic operation unit including four AND and two OR logic gates is proposed and experimentally demonstrated. It is realized using multiple intra‐mode four‐wave mixing (FWM) processes in a multimode silicon waveguide for 2 × 10 Gbit/s non‐return‐to‐zero on–off‐keying (NRZ‐OOK) mode‐division multiplexing signals. The AND logic operation is realized via the non‐degenerate FWM processes, and the OR logic operation is realized by overlapping the two degenerate FWM idlers in frequency domain via appropriately selecting the dual‐mode pump wavelength. The two OR and four AND logic sequences are verified with NRZ‐OOK sequences for both TE0 and TE1 modes. We propose and experimentally demonstrate an on‐chip dual‐mode all‐optical multifunctional logic operation unit including four AND and two OR logic gates. It is realized using multiple intra‐mode four‐wave mixing (FWM) processes in a multimode silicon waveguide for 2 × 10 Gbit/s non‐return‐to‐zero on–off‐keying (NRZ‐OOK) mode‐division multiplexing signals. The two OR and four AND logic sequences are verified with NRZ‐OOK sequences for both TE0 and TE1 modes.

The authors propose and experimentally demonstrate an on‐chip all‐optical multicasting (AOM) for 40 Gbit/s mode‐division‐multiplexed quadrature phase‐shift keying (MDM‐QPSK) signals based on a parallel dispersion‐engineered multimode non‐linear silicon waveguide. Five dual‐mode multicast wavelengths are successfully obtained on the generate idlers, and the power penalties of all the multicast channels are less than 1.1 dB at the bit error rate (BER) of 3.8 × 10−3. The dual‐mode AOM scheme has the potential to promote the ability of optical cross‐connect in practical hybrid multiplexed networks including MDM channels. We propose and experimentally demonstrate an on‐chip all‐optical multicasting (AOM) for 40 Gbit/s mode‐division‐multiplexed quadrature phase‐shift keying (MDM‐QPSK) signals based on a parallel dispersion‐engineered multimode nonlinear silicon waveguide. Five dual‐mode multicast wavelengths are successfully obtained on the generate idlers, and the power penalties of all the multicast channels are less than 1.1 dB at the bit error rate (BER) of 3.8×10−3. The dual‐mode AOM scheme has the potential to promote the ability of optical cross‐connect in practical hybrid multiplexed networks including MDM channels.

Photonic quantum metrology enables the measurement of physical parameters with precision surpassing classical limits by using quantum states of light. However, generating states providing a large metrological advantage is hard because standard probabilistic methods suffer from low generation rates. Deterministic protocols using non-linear interactions offer a path to overcome this problem, but they are currently limited by the errors introduced during the interaction time. Thus, finding strategies to minimize the interaction time of these non-linearities is still a relevant question. In this work, we introduce and compare different deterministic strategies based on continuous and programmable Jaynes–Cummings and Kerr-type interactions, aiming to maximize the metrological advantage while minimizing the interaction time. We find that programmable interactions provide a larger metrological advantage than continuous operations at the expense of slightly larger interaction times. We show that while for Jaynes–Cummings non-linearities the interaction time grows with the photon number, for Kerr-type ones it decreases, favoring the scalability to big photon numbers. Finally, we also optimize different measurement strategies for the deterministically generated states based on photon-counting and homodyne detection.

Optical trapping, also known as optical tweezing or optical levitation, is a technique that uses highly focused laser beams to manipulate micro- and nanoscopic particles. In optical traps driven by high-energy pulses, material non-linearity can result in unusual opto-mechanical effects, such as displaced equilibrium points. However, existing theoretical models of non-linear optical force on small particles consider smooth material dependence on the incident field strength alone, and not the feedback between the particle permittivity and internal field strength, which is, in turn, a function of the permittivity. The hysteresis effects of optical bistability in pulsed optical traps, therefore, elude existing optical force models. Here, we investigate a bistable optical trap, set up by counter-propagating ultrashort pulses, in which the optical force exerted on a particle depends not only on the field at its current location but on the historic trajectory of the particle in the trap. The developed formalism will be important for designing optical traps and nanoparticle manipulation in pulsed field for various applications, including potentially time crystal demonstrations.

Accurate knowledge of nonlinear optical parameters is essential for optimizing energy deposition in ultrafast laser 3D printing, yet these values remain undetermined for many commonly used materials. In this study, we address this gap by experimentally determining the two-photon absorption (TPA) and non-linear refraction coefficients ( and ) of the widely used SZ2080 resist with the photo-initiators (PI) IRG369 and BIS (Irgacure 369 and 4,4′ bis(diethylamino)-benzophenone or Michler’s ketone). Using the Z-scan method at 515 nm with a low repetition rate (1 kHz) to avoid thermal accumulation, we found that the nonlinear response of the host polymer has a considerable contribution to energy deposition despite the addition of the PI, as the host polymer makes up the majority of 99 % in the solution. The TPA cross section were 5.7 ± 0.4 GM (1 GM = 10  cm  s photon ) for pure SZ2080 ,  GM for IRG and  GM for BIS at 515 nm. The nonlinear refractive index for pure polymer was (85.3 ± 6) × 10  cm /TW, favoring a self-focusing, and was larger than that for PIs:  cm /TW (IRG369) and  cm /TW (BIS). Hence, the properties of the host material govern non-linear light propagation, although, in high numerical aperture focusing, self-focusing has a minor contribution to the variation of refractive index. Crucially, the determined TPA coefficients for pure SZ2080 provide experimental evidence that it can initiate polymerization without PIs, enabling a more sustainable and environmentally friendly fabrication route by avoiding the use of toxic additive compounds. These findings will allow for the estimation of exact energy deposition in 3D laser printing using ultrashort laser pulses and support the development of an initiator-free additive manufacturing approach.

In this paper, we review and discuss how nanoantennas may be used to largely enhance the nonlinear response of optical materials. For single nanoantennas, there have been tremendous advancements in understanding how to exploit the local field enhancement to boost the nonlinear susceptibility at the surface or sharp edges of plasmonic metals. After an overview of the work in this area, we discuss the possibility of controlling the optical nonlinear response using nanocircuit concepts and of significantly enhancing various nonlinear optical processes using planar arrays of plasmonic nanoantennas loaded with χ(2) or χ(3) nonlinear optical materials, forming ultrathin, nanometer‐scale nonlinear metasurfaces, as optical nanodevices. We describe how this concept may be used to boost the efficiency of nonlinear wave mixing and optical bistability, due to the large local field enhancement at the nonlinear nanoloads associated with the plasmonic features of suitably tailored nanoantenna designs. We finally discuss three exciting applications of the proposed nonlinear metasurface: dramatically‐enhanced frequency conversion efficiency, efficient phase‐conjugation for super‐resolution imaging and large optical bistabilities.

Nonlinear optics has been a very dynamic field of research with spectacular phenomena discovered mainly after the invention of lasers. The combination of high intensity fields with resonant systems has further enhanced the nonlinearity with specific additional effects related to the resonances. In this paper we review a limited range of these effects which has been studied in the past decades using close-to-room-temperature atomic vapors as the nonlinear resonant medium. In particular we describe four-wave mixing and generation of nonclassical light in atomic vapors. One-and two-mode squeezing as well as photon correlations are discussed. Furthermore, we present some applications for optical and quantum memories based on hot atomic vapors. Finally, we present results on the recently developed field of quantum fluids of light using hot atomic vapors.

Entangled multiphoton is an ideal resource for quantum information technology. Here, narrow-bandwidth hyper-entangled quadphoton is theoretically demonstrated by quantizing degenerate Zeeman sub states through spontaneous eight-wave mixing (EWM) in a hot 85Rb. Polarization-based energy-time entanglement (output) under multiple polarized dressings is presented in detail with uncorrelated photons and Raman scattering suppressed. High-dimensional entanglement is contrived by passive non-Hermitian characteristic, and EWM-based quadphoton is genuine quadphoton with quadripartite entanglement. High quadphoton production rate is achieved from co-action of four strong input fields, and electromagnetically induced transparency (EIT) slow light effect. Atomic passive non-Hermitian characteristic provides the system with acute coherent tunability around exceptional points (EPs). The results unveil multiple coherent channels (~8) inducing oscillations with multiple periods (~19) in quantum correlations, and high-dimensional (~8) four-body entangled quantum network (capacity ~65536). Coexistent hyper and high-dimensional entanglements facilitate high quantum information capacity. The system can be converted among three working states under regulating passive non-Hermitian characteristic via triple polarized dressing. The research provides a promising approach for applying hyper-entangled multiphoton to tunable quantum networks with high information capacity, whose multi-partite entanglement and multiple-degree-of-freedom properties help optimize the accuracy of quantum sensors.

The alternating property optimization (POPT) approach was employed to optimize the (hyper)polarizabilities of donor–acceptor-substituted polyfuran (PFu). The capability of the alternating POPT to design systems with specific properties was further demonstrated by the results, and its accuracy was validated. In both the αzz-maximizing and αzz-minimizing POPT, the selected monomers exhibited clear and consistent patterns, which may provide useful insights for the future design of PFu-based materials. Combined with the POPT results, the comparison of CPU time between the alternating POPT and the existing simultaneous POPT further demonstrated the reliability and efficiency of alternating POPT while handling systems growing along multiple directions.

Configurable and scalable continuous variable (CV) quantum networks for measurement-based quantum information protocols or multipartite quantum communication schemes can be obtained via parametric down conversion (PDC) in non-linear waveguides. In this work, we exploit symmetric group velocity matching (SGVM) to engineer the properties of the squeezed modes of the PDC. We identify type II PDC in a single waveguide as the best suited process, since multiple modes with non-negligible amount of squeezing can be obtained. We explore, for the first time, the waveguide dimensions, usually only set to ensure single-mode guiding, as an additional design parameter ensuring indistinguishability of the signal and idler fields. We investigate here potassium titanyl phosphate (KTP), which offers SGVM at telecommunications wavelengths, but our approach can be applied to any non-linear material and pump wavelength. This work paves the way toward the engineering of future large-scale quantum networks in the CV regime.