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Exciton polaritons, quasiparticles that strongly integrate transition metal dichalcogenides with large exciton binding energies and optical fields, exhibit unique properties due to their strong excitonic nonlinearity. However, intrinsic absorption losses pose a fundamental obstacle to all-optical tunability in exciton-polaritons due to the relatively broad resonance spectra. Therefore, it is necessary to determine structural configurations based on transition metal dichalcogenides to enhance the field distribution. Herein, the experimental details of a narrow trapped-mode based on asymmetric WS2 localized exciton-polaritons dual gratings are presented. The transmission value at the trapped mode wavelength can be tuned from 0.844 to 0.53 for an excitation power of 14.93 MWcm−2 with a pump wavelength of 366 nm. This is attributed to the narrow trapped-mode resonance and strong field enhancement in the asymmetric gratings. A relaxation time of approximately 35 ps is obtained, which is determined by the exciton lifetime of the WS2 flake. This work provides a foundation for the application of exciton-polaritons in all-optical devices.

All-optical tunable on-chip plasmon-induced transparency is realized in integrated plasmonic circuits based on two surface-plasmon-polaritons absorption induced polymerization of SU-8 photoresist. Owing to the enhanced interaction between surface plasmon polaritons and SU-8 guaranteed by the slow light effect around the transparency window and the strong light confinement effect of the plasmonic nanocavity modes, a continuous shift range of 24 nm in the central wavelength of the transparency window was obtained. The threshold power of the two surface-plasmon-polaritons absorption induced polymerization of SU-8 was as low as 100 μW, which is three orders of magnitude less than previous reports.

We demonstrate a continuously tunable photonic crystal with several picoseconds response, which is fabricated through a self-assembly formation method of polystyrene spheres. The large optical nonlinearity originates from the delocalization of the conjugated π-electron along polymer chains. The pump and probe scheme is adopted to measure the transmission changes based on the optical Kerr effect. The dynamic shift of the photonic band gap is studied. It is found that the band gap shifts about 13 nm when the input peak intensity is 40.4 GW/cm2, which is in agreement with the theoretical predictions.

An ultrafast and low-power all-optical tunable metamaterial-induced transparency is realized, using polycrystalline barium titanate doped gold nanoparticles and multilayer tungsten disulfide microsheets as nonlinear optical materials. Large nonlinearity enhancement is obtained associated with quantum confinement effect, local-field effect, and reinforced interaction between light and multilayer tungsten disulfide. Low threshold pump intensity of 20 MW/cm2 is achieved. An ultrafast response time of 85 ps is maintained because of fast carrier relaxation dynamics in nanoscale crystal grains of polycrystalline barium titanate. This may be useful for the study of integrated photonic devices based on two-dimensional materials.

Composite modulation of Fano resonance by using electric-field and microcavity simultaneously is realized in a plasmonic microstructure, which consists of a gold nanowire grating inserted into a Fabry-Perot microcavity composited of a liquid crystal layer sandwiched between two indium tin oxide layers. The Fano resonance wavelength varies with the applied voltage and the microcavity resonance. A large shift of 48 nm in the Fano resonance wavelength is achieved when the applied voltage is 20 V. This may provide a new way for the study of multi-functional integrated photonic circuits and chips based on plasmonic microstructures.

Nanoscale multichannel filter is realized in plasmonic circuits directly, which consists of four plasmonic nanocavities coupled via a plasmonic waveguide etched in a gold film. The feature device size is only 1.35 μm, which is reduced by five orders of magnitude compared with previous reports. The optical channels are formed by transparency windows of plasmon-induced transparencies. A shift of 45 nm in the central wavelengths of optical channels is obtained when the plasmonic coupled-nanocavities are covered with a 100-nm-thick poly(methyl methacrylate) layer. This work opens up the possibility for the realization of solid quantum chips based on plasmonic circuits.

An all-optical tunable double plasmon-induced transparency is realized in a photonic metamaterial coated on the surface of a nanocomposite layer made of polycrystalline indium-tin oxide doped with gold nanoparticles. The local-field effect, quantum confinement effect, and hot-electron injection ensure a large optical nonlinearity for the nanocomposite. A shift of 120 nm in the central wavelength of transparency windows is reached under excitation with a weak pump laser with an intensity of 21 kW/cm2. Compared with previous reports, the threshold pump intensity is reduced by five orders of magnitude, while an ultrafast response time of 34.9 ps is maintained.

All-optical tunable plasmonic-mode coupling is realized in a nonlinear photonic metamaterial consisting of periodic arrays of gold asymmetrically split ring resonators, covered with a poly[(methyl methacrylate)-co-(disperse red 13 acrylate)] azobenzene polymer layer. The third-order optical nonlinearity of the azobenzene polymer is enormously enhanced by using resonant excitation. Under excitation with a 17-kW/cm2, 532-nm pump light, plasmonic modes shift by 51 nm and the mode interval is enlarged by 30 nm. Compared with previous reports, the threshold pump intensity is reduced by five orders of magnitude, while extremely large tunability is maintained.

We report an all-optical logic binary encoder based on two asymmetric plasmonic nanogrooves etched in a gold film coated a polyvinyl alcohol layer. The physical mechanism originates from the unique capability of plasmonic nanogrooves in modulating the propagation properties of surface plasmon polaritons. The incident signal lights dropping in different wavelength regions are endowed with different logic state encodings. In such an ultracompact device with a feature size of only 2.4 μm, the coupling of free-space signal lights to surface plasmon polaritons and the on-chip encoding are integrated together, which is much suitable for practical integration applications.

We report an ultrafast and low-power all-optical tunable plasmon-induced transparency in a plasmonic nanostructure consisting of a gold nanowire grating embedded in a polycrystalline lithium niobate layer, realized based on strong quantum confinement enhancing nonlinearity. The all-optical tunability is realized based on the third-order nonlinear Kerr effect. A shift of 30 nm in the central wavelength of the transparency window is achieved under excitation of a pump light with an intensity as low as 7 MW/cm2. An ultrafast response time of 69 ps is reached because of ultrafast relaxation dynamics of bound electrons in polycrystalline lithium niobate.

An ultrafast all-optical tunable Fano resonance is realized in a nonlinear metamaterial composed of arrays of asymmetrically split rings etched in a gold film, coated with a polycrystalline lithium niobate layer. The metamaterial has a large optical nonlinearity because of strong nonlinearity enhancement associated with field reinforcement provided by plasmonic resonance, and quantum confinement effect provided by nanoscale crystal grains. A large shift of 23 nm in the Fano resonance wavelength is achieved under excitation of a weak pump light with an intensity of 15 MW/cm2. While an ultrafast response time of 48 ps is also maintained.

We report an ultrawide-band photon routing based on a chirped plasmonic grating, which consists of a gold film coated with a chirped dielectric grating made of organic polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]. The photon routing is realized based on rainbow-trapping like effect. An ultrawide operating bandwidth of 200 nm is reached through scanning near-field optical microscopy measurement. The tunable photon routing is reached through adjusting structural parameters of chirped plasmonic grating or using a pump light. A shift of 0.5 μm in the terminal channel is achieved for the 850-nm incident laser when the groove width changes from 150 to 180 nm.

We report an ultrafast all-optical tunable Fano resonance in a nonlinear ferroelectric photonic crystal made of polycrystal lithium niobate, which provides a large nonlinear susceptibility because of strong quantum size effect of nanoscale crystal grains. The femtosecond pump and probe method is adopted to measure the tunability of the Fano resonance based on the nonlinear optical Kerr effect. A 37-nm shift in the Fano resonance wavelength is obtained under excitation of a 30 MW/cm2 pump laser. An ultrafast response time of 43 ps is achieved due to fast relaxation dynamics of bound electrons in polycrystal lithium niobate.

We report a low-power all-optical switching in a two-dimensional nanocomposite photonic crystal microcavity made of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] doped with gold nanoparticles, realized based on surface plasmon resonance enhancing nonlinearity and dynamically tunable coupling of two asymmetric defect modes. Under excitation around the surface plasmon resonance peak, the value of the nonlinear susceptibility of the nanocomposite material reaches the order of 10−6 esu. A threshold photon energy as low as 700 fJ and an ultrahigh switching efficiency of 90% are realized simultaneously.

We report a multi-component nanocomposite material with large and ultrafast third-order nonlinearity, made of poly(3-hexylthiophene) doped with 1-(3-methoxycarbonyl)propyl-1-phenyl-(6,6)C61 and silver nanoparticles. Large nonlinear refractive index of the order of 10−7 cm2/W is reached by combining surface plasmon resonance enhancing nonlinearity and local-field enhancing nonlinearity. An ultrafast response time of 33.6 ps is achieved due to the enhanced charge transfer and exciton-exciton annihilation associated with surface plasmon resonance. An ultrafast photonic crystal all-optical switching with an ultralow pump intensity of 70 KW/cm2 is also realized.

We experimentally realize an all-optical diode in a photonic crystal heterostructure with broken spatial inversion symmetry. The physical mechanism is attributed to bandgaps only for certain wavevectors and the transition between different electromagnetic Bloch modes, without any nonlinearity and high power requirement. An ultralow photon intensity of 50 kW/cm2 and an ultrahigh transmission contrast of over 103 are reached simultaneously. Compared with previous reported all-optical diodes, the operating power is reduced by seven orders of magnitude, while the transmission contrast is enlarged by two orders of magnitude. This approach may open a way for the study of integrated photonic devices.

We report a nanocomposite material possessing large nonlinear optical coefficients and fast response simultaneously, which is made of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] doped with Ag nanoparticles. Under resonant excitation of the polymer matrix and Ag nanoparticles, the value of the nonlinear susceptibility reaches the order of 10−6 esu. A nonlinear response time of 35 ps is achieved due to the energy transfer from organic molecules to Ag nanoparticles. An ultrafast photonic crystal all-optical switching with an ultralow pump intensity of 0.2 MW/cm2 is realized.

An all-optical switching is demonstrated by use of defect mode in two-dimensional nonlinear photonic crystals made of polystyrene. Transmittance contrast of about 70% is achieved for the probe light. The dynamical shifts of the defect mode induced by pump intensity are measured and analyzed in detail. It is found that the defect mode shifts 5 nm under the excitation of 18.7GW∕cm2 pump intensity, which is in agreement with the theoretical predictions. Time response of the optical switching is smaller than the laser pulse of about 10 ps.

An ultrafast all-optical switching is demonstrated in an organic three-dimensional nonlinear photonic crystal with a response time as short as 120 fs. The operating wavelength of the optical switching is in the visible spectrum. The switching function is realized by a shift of the photonic band gap under optical pumping. It is found that the photonic band gap shifts about 10 nm with the excitation of 27.5GW∕cm2 pump laser.

An all-optical switching with high switch efficiency is realized based on two-dimensional nonlinear photonic crystal made of polystyrene. The prism-film coupling method is used to couple energy of probe light into photonic crystal waveguide. High transmittance contrast of more than 60% is realized for the probe light. Time response of the optical switching is around l0 ps. The dynamical shifts of photonic gap induced by pump light are measured and analyzed in detail. The photonic gap shifts l0 nm under the excitation of 16.7GW∕cm2 pump intensity, which is in agreement with the theoretical predictions.