Quantum GaAs/AlGaAs superlattice: multiphoton and high-frequency gain effects at room temperature

6 Jul 2022, 13:55
45m
Róża (Novotel Warszawa Centrum)

Róża

Novotel Warszawa Centrum

Marszałkowska 94/98 00-510 Warsaw POLAND Phone: +48 22 5960000 Fax: +48 22 5960647 E-Mail: H3383@accor.com WWW: https://all.accor.com/hotel/3383/index.en.shtml

Speaker

Prof. Gintaras Valušis (Department of Optoelectronics, Center for Physical Sciences and Technology, Sauletėkio al. 3, Vilnius, Lithuania)

Description

Semiconductor superlattices -- artificial periodic structures consisting of ultrathin layers where by variation of their width, doping level and profile one can tailor their optical and electronic properties in a desirable way – can be found as an attractive environment to investigate various high-frequency phenomena [1,2].
In the given communication, we present the first experimental observation of the cavityless dissipative parametric generation in subcritically doped GaAs/AlGaAs quantum superlattice. The effect, theoretically predicted more than a decade ago [3, 4] and being inherent to optical systems [5], was discovered in molecular beam epitaxy grown silicon doped GaAs/AlGaAs quantum superlattice. To enable uniform electric field in the structure the superlattice was sandwiched between non-ohmic contacts – Schottky contact on the top and heterostructure underneath. The structure was then processed into mezas and placed into a waveguide for microwave excitation of 8.45 GHz pump microwave radiation for DC biased experiment at room temperature.
A spectral response associated with both the nondegenerate and degenerate parametric processes and harmonics of the pump frequency was clearly demonstrated; generation at fractional frequencies due to several multiphoton processes occurring simultaneously was revealed. It is shown that the incident transverse electromagnetic microwave is transformed into a longitudinal electrostatic wave which propagates with electron drift velocity experiencing negative absorption due to the Esaki-Tsu nonlinearity. The established slow propagating drift-relaxation mode (with velocity of about 1000 times lower than the speed of light in the material) enables to reach tremendous high-frequency gain levels of 104 cm-1, which can be extended up to THz frequencies [6].

[1] C. Waschke et al., PRL 70, 3319 (1993).
[2] A. Ignatov et al., PRL 70, 1996 (1993).
[3] T. Hyart et al., APL 89, 132105 (2006).
[4] T. Hyart et al., PRL 98, 220404 (2007).
[5] R. Byer, Journal of Nonlinear Optical Physics and Materials 6, 549-592 (1997).
[6] V. Čižas et al., Phys. Rev. Lett., in press (2022).

Primary authors

Vladislovas Čižas (Department of Optoelectronics, Center for Physical Sciences and Technology, Sauletėkio al. 3, Vilnius, Lithuania) Liudvikas Subačius (Department of Optoelectronics, Center for Physical Sciences and Technology, Sauletėkio al. 3, Vilnius, Lithuania) Natalia V. Alexeeva (Department of Optoelectronics, Center for Physical Sciences and Technology, Sauletėkio al. 3, Vilnius, Lithuania) Dalius Seliuta (Department of Optoelectronics, Center for Physical Sciences and Technology, Sauletėkio al. 3, Vilnius, Lithuania) Timo Hyart (International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Al. Lotnikóv 32/46, 02-668 Warsaw, Poland; Department of Applied Physics, Aalto University, 00076 Aalto, Espoo, Finland) Klaus Köhler (Fraunhofeer-Institut für Angewandte Festkörperphysik, Tullastrasse 72, Freiburg D-79108, Germany) Kirill N. Alekseev (Department of Optoelectronics, Center for Physical Sciences and Technology, Sauletėkio al. 3, Vilnius, Lithuania; Department of Physics, Loughborough University, Loughborough LE11 3TU, United Kingdom) Prof. Gintaras Valušis (Department of Optoelectronics, Center for Physical Sciences and Technology, Sauletėkio al. 3, Vilnius, Lithuania)

Presentation Materials

There are no materials yet.
Your browser is out of date!

Update your browser to view this website correctly. Update my browser now

×