Seminar "Coherence-Correlations-Complexity", Dept. of Theoretical Physics, Wrocław University of Technology
Sala 320a bud. A-1, Politechnika Wrocławska
Thermal lasing in nanoscopic quantum systems
dr Paweł Karwat
Katedra Fizyki Teoretycznej WPPT PWr
With the rapid progress in miniaturization many types of devices have reached the nanoscale where quantum effects become more prevalent, e.g., quantum lasers. On properly designed nanoscopic quantum systems a heat gradient can lead to inversion in parts of it, that could be utilized e.g. for the generation of coherent light or phonons. I will take into consideration a theoretical concept of a nanoscopic quantum system representing the active medium of a thermal laser.
The model I am going to present consists of a central three-level system interacting with a two-level subunit at each side. Each two-level system is coupled to a heat bath. The different temperature of the baths imposes a heat gradient. The heat gradient leads to a flow of excitation from the hotter to the colder bath. At the central unit the flow is accompanied by the emission of a photon or phonon. For certain parameters, this transition can generate lasing.
In this talk, I will show that a positive inversion within the upper two levels of the central system takes place, which is a requirement to enable lasing.
The idea how to turn that concept into reality will be also discussed.
