arXiv subjects

Jacob B Khurgin

Publications and source records attributed to Jacob B Khurgin.

25 records · Page 2Linked to original sources

arXiv2016

Replacing Noble Metals with Alternative Materials in Plasmonics and Metamaterials: how good an idea?

Noble metals that currently dominate the fields of plasmonics and metamaterials suffer from large ohmic losses. New plasmonic materials, such as doped oxides and nitrides, have smaller material loss, and, using them in place of metals carries promise of reduced-loss plasmonic and metamaterial structures, with sharper resonances and higher field concentration. This promise is put to a rigorous analytical test in this work which reveals that having low material loss is not sufficient to have a reduced modal loss in plasmonic structures. To reduce the modal loss it is absolutely necessary for the plasma frequency to be significantly higher than the operational frequency. Using examples of nanoparticle plasmons and gap plasmons one comes to the conclusion that even in the mid-infrared spectrum metals continue to hold advantage over the alternative media. The new materials may still find application niche where the high absorption loss is beneficial, e.g. in medicine and thermal photovoltaics.

physics.optics↗

arXiv2015

Impact of surface collisions on enhancement and quenching of the luminescence near the metal nanoparticles

The fact that surface-induced damping rate of surface plasmon polaritons (SPPs) in metal nanoparticles increases with the decrease of particle size is well known. We show that this rate also increases with the degree of the mode confinement, hence damping of the higher order nonradiative SPP modes in spherical particles is greatly enhanced relative to damping of the fundamental (dipole) SPP mode. Since higher order modes are the ones responsible for quenching of luminescence in the vicinity of metal surfaces, the degree of quenching increases resulting in a substantial decrease in the amount of attainable enhancement of the luminescence

physics.optics↗

arXiv2014

Ultimate limit of field confinement by surface plasmon polaritons

We show that electric field confinement in surface plasmon polaritons propagating at the metal/dielectric interfaces enhances the loss due to Landau damping and which effectively limits the degree of confinement itself. We prove that Landau damping and associated with it surface collision damping follow directly from Lindhard formula for the dielectric constant of free electron gas Furthermore, we demonstrate that even if all the conventional loss mechanisms, caused by phonons, electron-electron, and interface roughness scattering, were eliminated, the maximum attainable degree of confinement and the loss accompanying it would not change significantly compared to the best existing plasmonic materials, such as silver.

physics.optics↗

arXiv2014

Multi-phonon-assisted absorption and emission in semiconductors and its potential for laser refrigeration

Laser cooling of semiconductors has been an elusive goal for many years, and while attempts to cool the narrow gap semiconductors such as GaAs are yet to succeed, recently, net cooling has been attained in a wider gap CdS. This raises the question of whether wider gap semiconductors with higher phonon energies and stronger electron-phonon coupling are better suitable for laser cooling. In this work we develop a straightforward theory of phonon-assisted absorption and photoluminescence of semiconductors that involves more than one phonon and use to examine wide gap materials, such as GaN and CdS and compare them with GaAs. The results indicate that while strong electron-phonon coupling in both GaN and CdS definitely improves the prospects of laser cooling, large phonon energy in GaN may be a limitation, which makes CdS a better prospect for laser cooling.

physics.optics↗

arXiv2013

Spasers, VCSELs, and Surface plasmon emitting diodes (SPED): their unique features and figures of merit

We compare fundamental characteristics of proposed electrically pumped subwavelength plasmonic lasers (spasers) with ubiquitous all-dielectric semiconductor micro-lasers (VCSEL) and indicate their close similarities as well as large differences in performance (threshold, efficiency, coherence and speed). These results should assist researchers in making informed choice of the emitter for each particular opto-electronic application.

physics.optics↗

arXiv2013

Plasmonic enhancement of the third order nonlinear optical phenomena: figures of merit

Recent years have seen increased interest to plasmonic enhancement of nonlinear optical effects, yet there remains an uncertainty of what are the limits of this enhancement. We present a simple and physically transparent theory of plasmonic enhancement of third order nonlinear optical processes achieved in plasmonic structures and show that while huge enhancement of effective nonlinear index can be attained, the most relevant figure of merit, the of phase shift per one absorption length remains very low. This means that while on one hand nonlinear plasmonic materials are not well suitable for applications requiring high efficiency, e.g. all-optical switching and wavelength conversion, on the other hand they can be very useful for the applications where the overall high efficiency is not a must, such as sensing.

physics.optics↗

arXiv2011

Scaling of losses with size and wavelength in nanoplasmonics and metamaterials

We show that, for the resonant metal-dielectric structures with sub-wavelength confinement of light in all three dimensions, the loss cannot be reduced significantly below the loss of the metal itself unless one operates in the far IR and THz regions of the spectrum or below. Such high losses cannot be compensated by introducing gain due to Purcell-induced shortening of recombination times. The only way low loss optical metamaterials can be engineered is with as yet unknown low loss materials with negative permittivity.

physics.optics↗