THEORETICAL STUDY OF EXCITED-STATE ABSORPTION IN GRAPHENE OXIDE AND ITS APPLICATION IN PHOTONIC SWITCHING

Abstract

Ever since it was realised that the silicon based electronics (semiconductor) industry will reach to saturation in near future, there has been a tremendous search for novel materials that might be able to replace silicon, particularly in applications related to switching and computation. In this thesis, one such novel material i.e. Graphene Oxide has been theoretically studied and its nonlinear optical properties have been thoroughly explored using the phenomenon of excited state absorption and the technique of rate equations. The results have been simulated using computer software and explanations are provided based on population and transmittance curves. The phenomena of saturable absorption and reverse saturable absorption have also been discussed in regards with the population curves for GO when excited by pulses of different width. Switching is the basic operation of establishing or breaking connection between two points in circuit. This is the basis for digital electronics that has revolutionalized the whole computer industry. GO shows all-optical characteristics that are desirable from a material useful for switching. So, the all-optical switching operation has been studied based on pump-probe method where one beam is used to modulate the intensity of the other and the possibility of GO being used in such applications has also been discussed. GO has proven to be a very interesting material that shows fascinating nonlinear optical properties. These properties if harvested properly, can help in developing all-optical switches based on GO that will be way faster, less power consuming and smaller than their silicon based electronic counterparts.