Ultrafast All‐Optical Switching

Abstract

Ultrafast all-optical switching, possessing the unique function of light controlling light, is an essential component of on-chip ultrafast optical connection networks as well as integrated logic computing chips. Ultrafast all-optical switching has attracted enormous research interests, the latest great developments of which have also yield progress in nanophotonics, integrated optics, nonlinear optics, material science, and optical communications, and so on. This review summarizes the fundamental realization principles, novel configurations, fancy materials, improved performance indexes, and ameliorated trigger method (transitioning from a traditional impractical free-spacevertical trigger to a more practical on-chip trigger) of ultrafast all-optical switching. Not only a systematic discussion of the current state-of-the art is provided, but also a brief outlook on the remaining challenges in the pursuit of the application of a practical on-chip ultrafast all-optical switching is also afforded.www.advopticalmat. de

Ultracompact all-optical full-adder and half-adder based on nonlinear plasmonic nanocavities

“…The measured linear transmission spectrum of the plasmonic waveguide side-coupled the plasmonic composite nanocavity C3 having the nano-Au:(IR140:MEH-PPV) cover layer is shown in Figure 3C, from which a sharp and high transmission peak appeared in a broad transmission forbidden band, indicating the formation of plasmoninduced transparency (PIT) window. This phenomenon could be contributed to the interference coupling between superradiant and subradiant modes provided by the composite nanocavity [43,44]. The central wavelength and the peak transmission of the transparency window were 820 nm and 82%, respectively, which are in agreement with the calculated one using the finite element method, as shown in Figure 3D.…”

“…Moreover, the surface plasmon resonance (SPR) peak of gold nanoflowers was around 800 nm owing to a relatively large size distribution [43]. Therefore, SPR resonant excitation of gold nanoflowers contributes to the third-order optical nonlinearity reinforcement of nano-Au:(IR140:MEH-PPV) nanocomposite when the incident signal light wavelength was around 800 nm [44]. According to our previous closed-aperture Z-scan experiment, the nonlinear refractive index was measured to be -1.3 × 10 −4 cm 2 /kW for the nanocomposite nano-Au:(IR140:MEH-PPV) excited by a 120-fs laser beam with a wavelength around 800 nm [43], which is eight orders of magnitude larger than that of SiO 2 , 1 × 10 −12 cm 2 /kW [45].…”

“…The measured linear transmission spectrum is shown in Figure 1D. A narrow transmission peak appeared in a broad transmission forbidden band, indicating the formation of PIT transparency window, which originates from the interference coupling between two resonance modes provided by the long and short plasmonic nanogrooves [43,44]. The central wavelength and the peak transmission of the transparency window were 800 nm and 80%, respectively, which are in agreement with the calculated one using the finite element method (employing the commercial software package COMSOL Multiphysics, Burlington, USA), as shown in Figure 1E.…”

“…Finally, a 100-nmthick nano-Au:(IR140:MEH-PPV) film was deposited onto the upper surface of the full-adder sample by using spin coating method, and the doping concentrations for IR140 and gold nanoflowers were 15% and 10%, respectively. The nanoflowers synthesized by HAuCl 4 have a solid core connected with plentiful pinnacles with a length ranging from 10 to 20 nm, the size of which has a relatively large distribution [43,44]. The SEM image for a 100-nm-thick nano-Au:(IR140:MEH-PPV) nanocomposite films deposited on a silica substrate is shown in Figure 1C.…”

“…As the incident power increased from 50 to 300 μW, the transmission increased from 15% to 80% for the 770-nm signal light propagating through the plasmonic waveguide side-coupled plasmonic nanocavity C3, while the transmission decreased from 81% to 20% for the 770-nm signal light propagating through the plasmonic waveguide side-coupled plasmonic nanocavity C4. According to the third-order nonlinear Kerr effect, the effective refractive index n of the nano-Au:(IR140:MEH-PPV) cover layer could be expressed as [43,44] 0 2 n n n I = +…”