All-Optical Emission Control and Lasing in Plasmonic Lattices

Abstract

We report on reversible all-optical emission control and lasing in plasmonic nanoparticle lattices. By incorporating photochromic molecules into the liquid gain medium composed of organic fluorescent molecules, we realize all-optical control over gain and absorption, the two key parameters associated with both conventional and nanoscale lasing. We demonstrate reversible photoswitching between two distinct modes of operation, 1) spontaneous emission to the lattice mode, characterized by broad emission linewidth, low emission intensity and large angular distribution and 2) lasing action, characterised by very narrow (sub-nm) linewidths due to emergence of increased gain and temporal coherence in the system, approximately three orders of magnitude increase in emission intensity, and narrow 0.7 degree angular divergence of the beam.A rate-equation model is employed to describe the operation of the switchable plasmonic laser. Our results provide the first demonstration of optically tunable losses 1 in plasmonic lattice lasers, which is an important milestone for the development of active plasmonics and paves the way for ultrafast all-optical switching of plasmonic nanolasers.

Lattice Resonances Induced by Periodic Vacancies in Arrays of Nanoparticles

“…The strong near-fields provided by lattice resonances play a crucial role for applications, such as nanolasing, in which the arrays interact with quantum emitters placed in their vicinity [37,60,61]. Specifically, in these systems, the lattice resonances couple with the emitters (usually quantum dots or dye molecules) that constitute the gain medium and provide the necessary feedback to achieve lasing [44,45,[62][63][64][65][66][67][68]. These modes can also strongly influence the emission patterns of the emitters [69,70].…”

Magnetic on-off switching of a plasmonic laser

“…Under circularly polarized excitation, angle-resolved photoluminescence measurements reveal a transition between lasing action and non-lasing emission as the nanodot magnetization is reversed. Our results introduce magnetization as a means of externally controlling plasmonic nanolasers, complementary to the modulation by excitation [5], gain medium [6,7] or substrate [8]. Further, the results show how effects of magnetization on light that are inherently weak become prominent at the lasing regime, inspiring studies of topological photonics [9][10][11].…”

Experimental Demonstration of Dark‐State Metasurface Laser with Controllable Radiative Coupling

“…Owing to their strong, sub-wavelength field confinement, surface plasmon-polariton modes have been successfully used for constructing lasers of sub-wavelength size. [2][3][4][5][6][7][8][9][10] However, the large ohmic losses associated with the metals, which are necessary for the plasmonic response, push the lasing threshold to high levels. Importantly, the radiation damping is closely connected with the type and symmetry of the oscillating plasmonic mode and, hence, it is difficult to control the outcoupled power for a given mode.…”