Локализация Энергии Лазерного Излучения В Оптико-Терагерцевом Преобразователе Ультракоротких Ик-Импульсов При Помощи Профилированных Сапфировых Волокон

Abstract

We report the seminal approach for localization of photocarriers in a photoconductive antenna (PCA)-emitter via the focusing element comprising the sapphire fiber. Using numerical simulation, we showed that at the certain ratio between the fiber diameter and the gap size, i.e. d/g = 22.5, one can attain a 35-fold enhancement of the laser irradiation in vicinity of the PCA electrodes. This provides the formation of subwavelength EM wave caustics located at the edges of the PCA electrodes which potentially gives rise to an increase of optical-to-terahertz conversion efficiency.