INTERACTION OF INFRARED ELECTROMAGNETIC WAVES IN RESONANT LAYERED STRUCTURES WITH n-GaAs SEMICONDUCTOR FILM

2009 ◽  
Vol 18 (01) ◽  
pp. 73-83
Author(s):  
V. GRIMALSKY ◽  
S. KOSHEVAYA ◽  
J. ESCOBEDO-A
Keyword(s):  
Electric Field ◽  
Total Internal Reflection ◽  
Electromagnetic Waves ◽  
Oblique Incidence ◽  
Modulation Instability ◽  
Semiconductor Film ◽  
Gaas Film ◽  
Short Pulses ◽  
Bias Electric Field ◽  
Resonant Transmission

Interaction of infrared electromagnetic (EM) waves in a layered structure with n- GaAs film is investigated theoretically. An oblique incidence of EM wave is considered, when the total internal reflection and resonant transmission occur. It is demonstrated that this structure modulates effectively the infrared EM wave. The modulation mechanism is due to the transfer of electrons from the upper valley to the higher ones in a strong bias electric field. An interaction of strong incident infrared EM pulses with this structure is also considered in the case of the absence of a bias electric field. Both the nonlinear switching of short pulses and the modulation instability of long strong pulses take place.

scholarly journals Design of a Liquid-Crystal-Tunable Terahertz Demultiplexer Based on a Metal-Insulator-Metal Waveguide

2019 ◽  
Vol 9 (4) ◽  
pp. 644
Author(s):  
Xue-Shi Li ◽  
Naixing Feng ◽  
Yuan-Mei Xu ◽  
Liang-Lun Cheng ◽  
Qing Liu
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Metal Insulator ◽  
Resonance Modes ◽  
External Bias ◽  
Bias Electric Field ◽  
Metal Waveguide ◽  
Metal Insulator Metal ◽  
Fabry Perot ◽  
Mim Waveguide

A tunable demultiplexer with three output channels infiltrated by liquid crystal (LC) is presented, which is based on a metal-insulator-metal (MIM) waveguide. The operating frequencies of the three output channels can be tuned simultaneously at will by changing the external bias electric field applied to the LC. By analyzing the Fabry-Pérot (FP) resonance modes of the finite-length MIM waveguide both theoretically and numerically, the locations of the three channels are delicately determined to achieve the best demultiplexing effects. Terahertz (THz) signals input from the main channel can be demultiplexed by channels 1, 2 and 3 at 0.7135 THz, 1.068 THz and 1.429 THz, respectively. By applying an external electric field to alter the tilt angle of the infiltrating LC material, the operating frequencies of channels 1, 2 and 3 can be relatively shifted up to 12.3%, 9.6% and 9.7%, respectively. The designed demultiplexer can not only provide a flexible means to demultiplex signals but also tune operating bands of output channels at the same time.

THz pulse train generation through ultrafast development of surface plasmon-polariton modulation instability

2021 ◽  
Author(s):  
Dmitry A Korobko ◽  
Igor O. Zolotovskii ◽  
Sergey Moiseev ◽  
Alexei S. Kadochkin ◽  
Vyacheslav Svetukhin
Keyword(s):  
Surface Plasmon ◽  
Electromagnetic Waves ◽  
Surface Plasmon Polariton ◽  
Modulation Instability ◽  
Frequency Comb ◽  
Nonlinear Effects ◽  
Wave Dispersion ◽  
Instability Effect ◽  
Plasmon Polariton ◽  
Plasmon Wave

Abstract Propagation of high-intensity electromagnetic waves in a waveguide structure could initiate nonlinear effects resulting in drastic changes of their spatial and temporal characteristics. We study the modulation instability effect induced by propagation of surface plasmon polaritons in a silver thin-film waveguide. The nonlinear Schrodinger equation for propagating surface plasmon wave is obtained. It is shown numerically that the modulation instability effect can give rise to ultrafast spatial redistribution and longitudinal localization of surface plasmon-polariton wave energy in subwavelength scale. The dependence of plasmon wave dispersion and nonlinear characteristics on metal film thickness is considered. We demonstrate that the use of films with the thickness varying along the waveguide length allows reduction of the generated pulse width and increase of frequency comb bandwidth. The proposed technique is promising for design of ultra-compact (tens of nm) optical generators delivering pulse trains with the repetition rate higher than 1THz.

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