Nanoscale nonlinear plasmonics in photonic waveguides and circuits

Abstract

Optical waveguides are the key building block of optical fiber and photonic integrated circuit technology, which can benefit from active photonic manipulation to complement their passive guiding mechanisms. A number of emerging applications will require faster nanoscale waveguide circuits that produce stronger light-matter interactions and consume less power. Functionalities that rely on nonlinear optics are particularly attractive in terms of their femtosecond response times and terahertz bandwidth, but typically demand high powers or large footprints when using dielectrics alone. Plasmonic nanostructures have long promised to harness metals for truly nanoscale, energy-efficient nonlinear optics. Early excitement has settled into cautious optimism, and recent years have been marked by remarkable progress in enhancing a number of photonic circuit functions with nonlinear plasmonic waveguides across several application areas. This work presents an introductory review of nonlinear plasmonics in the context of guided-wave structures, followed by a comprehensive overview of related experiments and applications covering nonlinear light generation, all-optical signal processing, terahertz generation/detection, electro optics, quantum optics, and molecular sensing.

Organic Electro-Optics and Optical Rectification: From Mesoscale to Nanoscale Hybrid Devices and Chip-Scale Integration of Electronics and Photonics

“…Comparison of various EO device technologies is extensively reviewed in the literature. ,,− ,,,,,,, Meaningful comparison of different technologies is complex and can be misleading. Some general comments can be made.…”

“…A sea change in electro-optic technology (and ultimately, optical rectification technology) has occurred with (1) the advent of the subwavelength technologies of silicon photonics and plasmonics ,− and with (2) theory-guided improvement of the r 33 values and other relevant properties of OEO materials. ,, Silicon photonics and plasmonics have facilitated a dramatic reduction in device dimensions. Plasmonic–organic hybrid (POH) device lengths can be reduced to less than 10 μm and electrode spacings to less than 50 nm (nm).…”

“…We do, however, provide examples of typical SFDR and bit error rate (BER) performance for hybrid organic EO devices. In a like manner, we do not give a detailed comparison of modulator technologies (modulated lasers, Pockels effect modulators, and modulator based on electro-absorption and other mechanisms) as these are covered in many cited reviews. ,,− ,,,,− We do note that new classes of EO materials and devices (e.g., EO devices based on materials such as ITO) are emerging and merit attention. Our perspective is to provide insight into coordinated development of OEO materials and related devices relevant to commercial (or potentially commercial) electro-optic and optical rectification technologies.…”

Second-harmonic generation in plasmonic waveguides with nonlocal response and electron spill-out

“…Plasmonic systems allow miniaturization below the diffraction limits thanks to surface plasmon-polariton (SPP) modes -the resonant collective oscillations of free electrons (FEs) -appearing in materials with a high carrier concentration (i.e., metals and heavily doped semiconductors) and arising at the interface with a dielectric because of the interaction with an external electromagnetic (EM) excitation. Localization of light associated to SPPs modes is naturally promising for the enhancement of intensity-dependent phenomena [25][26][27][28][29][30][31][32][33][34][35]. * cristian.ciraci@iit.it Functionalities based on nonlinear optics are very attractive in terms of their femto-second response times and terahertz bandwidths.…”

“…On the other hand, plasmonic waveguides can sustain subwavelength field localization for the entire propagation length, thereby providing ideally larger volumes of interactions. Indeed, hybrid dielectric-plasmonic waveguides have been reported with a variety of nonlinear applications (see for example a comprehensive review on latest advances in nonlinear plasmonic waveguides [33]). Most waveguide systems can be easily studied by decoupling the propagation and transverse problems [39][40][41][42][43][44][45][46].…”