Reverse mode switching of the random laser emission in dye doped liquid crystals under homogeneous and inhomogeneous electric fields

Lévy Statistics and the Glassy Behavior of Light in Random Fiber Lasers

“…We start by reviewing the theoretical background [73][74][75][76][77][78][79][80] underlying the diverse photonic behaviors displayed by RLs. In a photonic system with intrinsic disorder, arising either from the inherent optical random noise or from the presence of randomly-located light scatterers (e.g., micro or nanoparticles [12][13][14][15][16][17], or dielectric nanocrystals doped with rare-earth ions [20,21]), the amplitudes a k of the electromagnetic modes generally present stochastic dynamics. The Langevin approach is thus a suitable theoretical framework to describe such dynamics through the following set of equations,…”

“…That report was followed by a great number of papers from different authors that investigated other physical systems for efficient RL operation. A large variety of materials have been tested in the past years, and recent publications on RLs describe, for example, experiments with dyes dissolved in transparent liquids, gels or liquid crystals with suspended micro or nanoparticles as light scatterers [12][13][14][15][16][17], powders of semiconductor quantum dots [18,19], dielectric nanocrystals doped with rare-earth ions [20,21], polymers and organic membranes doped by luminescent molecules [22][23][24][25][26][27], semiconductor and metallic nanowires structures [28][29][30][31], and even atomic vapors that present interesting analogies with astrophysical lasers [32].…”

Magnetically controllable random laser in ferromagnetic nematic liquid crystals

“…Because the laser action is correlated with the orientational direction of liquid crystals [15], it could respond to the molecular reorientation by a variety of external stimuli. In fact, the wavelength, intensity and polarization of the random laser in NLCs can be controlled by electrical [16][17][18][19], thermal [13,20] and magnetic [19] stimuli, and the alignment of LC cells [15,21]. In particular, the optical switching owing to the molecular reorientation in a magnetic field [22] has some advantages in remote operability [8].…”

Alumina particles doped in a polymer film act as scatterers for random laser generation

“…The former requires some proper scatterers as well as a proper gain medium and is thus possibly constructed in a haphazard architecture; however, a specialized structure is indispensable for a random laser based on an electrical pump, such as a P-I-N junction, a metal-insulatorsemiconductor structure or a metal-semiconductor-semiconductor [24]. The parameters that determined the formation of a random laser have also been investigated in recent years, such as an electrical field [25], temperature [26], polarization [27], pressure [28] and pH [29].…”