How an Electrically Active and Magnetically Quantized Quantum Wire Can Act As an Optical Amplifier

The fundamental issues associated with the magnetoplasmon excitations are investigated in an electrically active quantum wire characterized by a confining harmonic potential and subjected to a perpendicular magnetic field in the symmetric gauge. Essentially,
we embark on the device aspects of the intersubband collective (magnetoroton) excitation which observes a negative group velocity
between the maxon and the roton. A comprehensive study of the effect of an applied magnetic field and an electric field reveals some fascinating features regarding the existence of the magnetoroton excitation, which is crucial to track the action. The computation of
the gain coefficient suggests an interesting and important application: the electronic device based on such magnetoroton modes can
act as an optical amplifier. [See, for example, similar studies but in an electrically passive quantum wire in: M.S. Kushwaha,
Phys. Rev. B 78, 153306 (2008); J. Appl. Phys. 109, 106102 (2011); Mod. Phys. Lett. B 28, 1430013 (2014).]