Figure of merit for Kerr nonlinear plasmonic waveguides

Abstract

Plasmonic waveguides are promising in many applications because of their subwavelength field confinement, which can strongly enhance light-matter interactions. Nevertheless, how to efficiently evaluate their Kerr nonlinear performance is still an open question because of the presence of relatively large linear losses. Here a simple and versatile figure of merit (FOM) is proposed for Kerr nonlinear waveguides with linear losses. To derive the FOM, a generalized full-vectorial nonlinear Schrödinger equation governing nonlinear pulse propagation in a lossy waveguide is developed, and an approximate analytic solution of the degenerate four wave mixing conversion efficiency is derived and validated. The effectiveness of the FOM is verified with an all-plasmonic and a hybrid-plasmonic waveguide configuration. Rigorous results show that the optimal waveguide length for the highest conversion efficiency is ln 3 times the attenuation length. At this length, the upper limits of the conversion efficiency and the nonlinear phase shift are determined by the FOM. These results provide fundamental theory and useful guidance in exploring plasmonic waveguides for nonlinear optical applications.

Crosstalk Suppressed High Efficient Mode-Selective Four-Wave Mixing Through Tailoring Waveguide Geometry

“…In accordance with [18] and [19], the Type 1 CEs monotonically increase in the length region from 1 to 10 mm. However, the Type 3 CEs periodically fluctuate with the waveguide length.…”

“…To be noted, the research interests for both single-and multi-mode nonlinear devices were usually focused on optimizing waveguide transverse geometry parameters [12], [13], [17]. Actually, the longitudinal design is of equal importance to nonlinear waveguides for its great influence on nonlinear efficiency and large misalignment tolerance, as demonstrated for single-mode cases [18], [19]. Especially, the longitudinal design will further affect the inter-channel crosstalk in multimode cases.…”

Record Purcell factors in ultracompact hybrid plasmonic ring resonators

“…An alternative approach to increase the Purcell factor is to reduce V eff . To this end, subwavelength plasmonic structures have emerged as potential platforms for implementing high Purcell factor cavities (9)(10)(11)(12)(13)(14)(15). In contrast to dielectric waveguides that guide light through total internal reflection (TIR), electromagnetic waves are guided in the form of surface plasmon polaritons (SPPs) in plasmonic waveguides, which are guided along metal-dielectric interfaces (16)(17)(18)(19).…”

Two-dimensional plasmonic waveguides for nanolasing and four-wave mixing

“…)·ˆ( || ) is the attenuation length, the length over which the intensity reduces by a factor e, and the gain confinement factor Γ G [37,38] and the nonlinear effectiveness EFF NL [28] can be written as where Z 0 is the vacuum impedance, and f 2 3ln 3 = ( ( )) ℓ accounts for modal loss [36]. Comparing equations (3) and (4), or equation (7), we find that the only difference between k 0 /g th or Γ G for plasmonic nanolasers and n max  D or EFF NL /f ℓ for plasmonic DFWM devices is that the latter has an additional factor U in the integral kernel of the numerator.…”