Investigating the magneto-optics in quantum wires for designing the optical amplifiers

Quantum wires occupy a unique status among the semiconducting nanostructures with reduced dimensionality
-- no other system seems to have engaged researchers with as many appealing features to pursue.
This paper aims at a core issue related with the magnetoplasmon excitations in the quantum wires
characterized by the confining harmonic potential and subjected to a longitudinal electric field and a
perpendicular magnetic field in the symmetric gauge. Crucial to this inquiry is an
intersubband collective excitation that evolves into a magnetoroton -- above a threshold value of magnetic
field -- which observes a negative group velocity between the maxon and the roton. The evidence of negative
group velocity implies anomalous dispersion in a gain medium with the population inversion that forms the
basis for the lasing action of lasers^1-6. Thus, the technological pathway that unfolds is the route to devices
exploiting the magnetoroton features for designing the novel optical amplifiers at nanoscale and hence
paving the way to a new generation of lasers. 1. M. S. Kushwaha, Phys. Rev. B 76, 245315 (2007); 2. Phys.
Rev. B 78, 153306 (2008); 3. J. Appl. Phys. 109, 106102 (2011); 4. Mod. Phys. Lett. B 28 1430013 (2014); 5.
Europhys. Lett. 123, 34001 (2018); 6. Mod. Phys. Lett. B 33 1950062 (2019).