Pliable Polaritons: Wannier Exciton Plasmon Coupling in Metal Semiconductor Structures

Plasmonic structures are known to support the modes with subwavelength volumes in which the field matter interactions are greatly enhanced. Coupling between the molecular excitations and plasmons leading to formation of plexcitons has been investigated for a number of organic molecules. However, plasmon-exciton coupling in metal semiconductor structures have not experienced the same degree of attention. In this work we show that the very strong coupling regime in which the Rabi energy exceeds the exciton binding energy is attainable in semiconductor cladded plasmonic nanoparticles and leads to formation of Wannier Exciton Plasmon Polariton (WEPP) that is bound to the metal nanoparticle and characterized by dramatically smaller (by factor of few) excitonic radius and correspondingly higher ionization energy. This higher ionization energy exceeding approaching 100meV for the CdS/Ag structures may make room temperature Bose Einstein condensation and polariton lasing in plasmonic/semiconductor structures possibl

Photonic Time Crystals and Parametric Amplification: similarity and distinction

Photonic Time crystals (PTC) arise in time-modulated media when the frequency of modulation of permittivity is on the order of twice the frequency of light and are manifested by the generation and amplification of so-called time reversed waves propagating in the direction opposite to the incoming light. Superficially, the observed phenomenon bears resemblance to the widely known phenomena of optical parametric generation (OPG) and amplification (OPA) using second or third order optical nonlinearities. I show that while indeed the same physical mechanism underpins both PTC and OPA , the difference arises from the boundary conditions. Thus , while dispersion for both PTC and OPA exhibit the same bandgap in momentum space, only in the case of PTC can one have propagation in that bandgap with exponential amplification. I also show that PTC can be engineered with both second and third order nonlinearities, and that rather unexpectedly, modulating permittivity on the ultrafast (few fs) rate is not a necessity, and that one can emulate all the PTC features using materials with a few picoseconds response time commensurate with the propagation time through the medium

Nonlinear Optics: a look from the interaction time viewpoint and what it portends

I present a simple view of nonlinear optcal phenomena as being determined mostly by the length of interaction time between photons and matter. This may explain why in the last decades the progress in developing better nonlinear materials has not been as rapid as wished. A few tentative routes towards possible improvements in the efficiency of nonlinear optical phenomena are suggested

Optical isolation by temporal modulation: size, frequency, and power constraints

Optical isolators are indispensable components of optical networks. Magneto-optic isolators have excellent operating characteristics, including low-to-no power consumption, but are not well suited for on-chip integration. The technique of temporal modulation of dielectric constant offers an alternative way to achieve isolation without magnetic field but is not without its own drawbacks. In this work I examine diverse methods of optical isolation via temporal modulation and show that independent on whether modulation is achieved by carrier injection, Pockels and acousto-optic effects, or any other conceivable method, there is essentially the same set of constraints on footprint, modulation frequency, and, most important, on power consumption required to achieve full isolation without excessive insertion loss. This power is estimated to be on the order of at least a hundred of milliwatts and whether this requirement is acceptable will depend on ongoing progress of both magneto-optic and time modulated integrated technologies