An efficient frequency conversion scheme of surface-plasmon polariton ͑SPP͒ is proposed for nonlinear plasmonic applications. Lossy coupling wave equations are deduced to describe the interaction among involved SPP frequency components. The reciprocal vector of a microstructure could partially compensate the SPP wave-vector mismatch through quasiphase matching ͑QPM͒. As an example, the frequency doubling of SPP over a periodically poled lithium niobate is studied. The high-field concentration of SPP greatly enhanced the second-harmonic generation ͑SHG͒ over a short traveling distance. Although the high attenuation of SPP affects the SHG severely, a long-range SPP SHG is further proposed and investigated, which shows great efficiency improvement. The applications of QPM SPP frequency conversion are also discussed showing great potentials in miniature plasmonic sources and processors.
We propose a bidirectional tunable optical diode based on a periodically poled lithium niobate (PPLN) with defect. An acoustic wave propagates together with the light beam so that a collinear photon-phonon interaction happens, which affects the nonlinear optical processes in PPLN. The fundamental wave exhibits an optical diode effect, i.e., the light only may travel toward a single direction while the opposite way is isolated. However, the acoustic wave could be used to adjust the contrast of optical isolation from -1 to 1. A direction-optional operation is thus realized. Moreover, the advantages of our tunable PPLN optical diode are also discussed.
Polarization independent sum frequency generation (SFG) is proposed in an electro-optic (EO) tunable periodically poled Lithium Niobate (PPLN). The PPLN consists of four sections. External electric field could be selectively applied to them to induce polarization rotation between the ordinary and extraordinary waves. If the domain structure is well designed, the signal wave with an arbitrary polarization state could realize efficient frequency up-conversion as long as a z-polarized pump wave is selected. The applications in single photon detection and optical communications are discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.