Controlling the transverse localization of THz waves in an InSb based disordered waveguide array using temperature

We propose that the transverse localization in a semiconductor-based disordered waveguide array can be made controllable in the terahertz (THz) regime by changing the ambient temperature. The standard scalar Helmholtz equation is used to describe THz wave propagation through the waveguide array. It is assumed that the waveguides are fabricated from the indium-antimonide (InSb) semiconductor, while the spacing between them is a dielectric. Disorder is introduced in the system by the random refractive index of the spacing medium. Our results demonstrate that the transverse width of the output intensity increases when increasing the temperature. This effect is attributed to the temperature-dependent electric permittivity of the used semiconductor. Then, the waveguides are composed of a dielectric and the spacing between them is filled with the InSb semiconductor. For this case, to introduce disorder, we assumed that the refractive indices of the waveguides are randomized. It is found that the output intensity becomes more localized with increasing temperature. However, further increasing the temperature leads to the delocalization of output intensity. The effect of spacing between adjacent waveguides on the threshold degree of disorder has also been investigated. (C) 2013 Optical Society of America