A Novel Metal Nanoparticles-Graphene Nanodisks-Quantum Dots Hybrid-System-Based Spaser

Abstract

Active nanoplasmonics has recently led to the emergence of many promising applications. One of them is spaser (surface plasmons amplification by stimulated emission of radiation) that has been shown to generate coherent and intense fields of selected surface plasmon modes that are strongly localized in the nanoscale. We propose a novel nanospaser composed of metal nanoparticlesgraphene nanodisks hybrid plasmonic system as its resonator and a quantum dots cascade stack as its gain medium. We derive the plasmonic fields induced by pulsed excitation through the use of the effective medium theory. Based on the density matrix approach and by solving the Lindblad quantum master equation, we get ultrafast dynamics of the spaser associated with coherent amplified plasmonic fields. The intensity of the latter is significantly affected by the width of the metallic contact and the time duration of the laser pulse used to launch the surface plasmons. The proposed nanospaser operates in the mid-infrared region that has received much attention due to its wide biomedical, chemical and telecommunication applications.

Spaser and Optical Amplification Conditions in Graphene-Coated Active Wires

“…7a). This reduction of the value of the critical gain with particle size is anticipated by the quasistatic expression (17), which shows that…”

Polarized Stimulated Emission of 2D Ensembles of Plasmonic Nanolasers

“…[ 14–18 ] To date, several implementations of spasers and plasmonic nanolasers have been investigated: nanospheres, [ 12 ] nanodisks, [ 19 ] nanoflakes, [ 20 ] nanowires, [ 21 ] nanorods, [ 22 ] nanotori; [ 23 ] a topological spaser [ 11 ] and free electron excited spaser [ 24 ] were proposed. Organic dyes, [ 12 ] carbon nanostructures, [ 25 ] transition metal dichalcogenides, [ 26 ] and their hybrids [ 27,28 ] can act as a gain medium. The properties of subwavelength lasers are constantly improving; several groups have dealt with low‐threshold for lasing, [ 29–32 ] multiwavelength lasing, [ 33 ] and high external quantum efficiency.…”

Spaser and optical amplification conditions in graphene-coated active wires

“…This reduction of the value of the critical gain with particle size is anticipated by the quasistatic expression of Eq. (17), which shows that |[ε di ] c | is an increasing function of R (note that the dependence on R is included in ω 2 0n ). It is interesting to note that this behavior, which is absent in metallic cylinders without a graphene cover, results from the graphene-nanocrystal plasmon hybridization and is highlighted when the effective plasma frequency ω on is comparable with the nanocrystal plasma frequency ω p (as is the case for the constitutive parameters chosen in this example).…”

“…In Ref. [17], the authors propose a graphene-metal hybrid plasmonic system surrounded by a quantum dots cascade stack as a nano spaser in the infrared. In addition, in Ref.…”