1 Fiber Optics, Devices and Non-linear Effects, Department of Photonics Engineering, Technical University of Denmark2 Department of Photonics Engineering, Technical University of Denmark3 Fiber Sensors and Supercontinuum Generation, Department of Photonics Engineering, Technical University of Denmark4 Teraherts Technologies and Biophotonics, Department of Photonics Engineering, Technical University of Denmark5 Center for Nanostructured Graphene, Center, Technical University of Denmark
This thesis builds around the investigation into using soft glass materials for midinfrared and THz applications. Soft glasses is a term that cov ers a wide range of chemical compositions where many are yet to be fully investigated. The work in this thesis is separated in two parts, the mid-infrared applications and the THz applications. In the mid-infrared, it is investigated whether soft glasses are a suitable candidate for supercontinuum generation (SCG). A few commercially available fluoride fibers are tested for their zero dispersion wavelength (ZDW), a key property when determining the possibility of SCG in a fiber. A group of soft glasses, namely the chalcogenides, are known to display two photon absorption (TPA) which could potentially limit the SCG when this is initiated within the frequency range where this nonlinear process occur. An analytic model is presented to estimate the soliton self frequency shift (SSFS), another key element in SCG, when TPA is present. To show the validity of this model, it is used with chalcogenide fiber parameters from the literature to show that a frequency shift is limited due to the TPA effect. It is only resent, that soft glass materials have come into focus for THz applications, thus these materials remain relatively unknown. A selection of GeAsSe chalcogenides is investigated to determine whether they have potential as transparent glasses for THz applications. In order to do so, these glasses are tested experimentally in both transmission and reflection measurements to determine the complex refractive index. Knowledge of the index and loss is key in determining if these glasses will be interesting candidates for future applications.