Nanomaterials are playing an increasing role in novel technologies, and it is important to develop optical methods to characterize them in situ.  To that end, backside absorbing layer microscopy (BALM) has emerged as a powerful tool, being capable to resolve sub-nanometer height profiles, with video-rate acquisition speeds and a suitable geometry to couple live experiments.  In the internship, several techniques involving BALM were developed, and applied to study optical and electrical properties of the transition metal dichalcogenide (TMD) monolayer MoS2, a type of 2-dimensional (2D) crystalline semiconductor.  A simulations toolkit was created in MATLAB to model BALM, a workflow to reliably extract linear intensities from the CMOS detector was realized, and 2D MoS2 was synthesized by chemical vapor deposition followed by transfer to appropriate substrates.  BALM data of the 2D MoS2 was acquired and combined with simulations, giving a preliminary result for its complex refractive index at 5 optical wavelengths.  In addition, the first steps towards coupling BALM with a gate biased 2D MoS2 field-effect transistor were explored.  To complement BALM measurements, the grown samples were also characterized by conventional optical microscopy, scanning electron microscopy, atomic force microscopy, photoluminescence spectroscopy, and Raman spectroscopy.  This work provides new additions to an existing platform of BALM techniques, enabling novel BALM experiments with nanomaterial systems.  In particular, it introduces a new alternative for local extraction of optical parameters and for probing of electrical charging effects, both of which are vital in the research and development of nano-optoelectronics.

The discoveries in applications of chirality in various areas of science seem to never cease to emerge. Chirality, being the property that some objects are geometrically distinguishable from their mirror image, is a tiny difference of vast importance. The fact that multiple biological structures are chiral is what permits life on Earth and its discovery had a severe impact on medical development. When the concept of quantum chirality was introduced, the connection between the chiral symmetry and the quantum states and operators that characterize quantum chirality was not particularly clear. It was shown that closed spin chains of an odd number of spins naturally had chiral states as eigenstates of a Hamiltonian describing Heisenberg and Dzyaloshinsky-Moriya (DM) interactions, and the symmetry of the system in direct relation to the chiral symmetry of the eigenstates quickly became of interest. The aim of this thesis is therefore to explore how quantum chirality is a chiral symmetry and to develop a scheme to create chiral states from systems that lack the required symmetry. The investigation showed that discretized probability current gives a good explanation to why the chiral states follow a chiral nature, but further examination is required in order to generalize a deeper connection between the probability current and the chiral states of spin chains. The results also indicated that it was possible to force open spin chains into purely chiral states, and into superpositions thereof, by time evolution. The scheme is still in its early stage and physical implementation and applications are yet to be explored. / Upptäckterna av tillämpningar av kiralitet inom ett flertal områden verkar ständigt öka i omfattning. Kiralitet är fenomenet att vissa objekt geometriskt kan särskiljas från sin spegelbild, vilket är en ringa skillnad men med väsentlig innebörd. Det faktum att flertalet biologiska strukturer är kirala är en förutsättning för liv på jorden och upptäckten av detta har haft en omfattande betydelse för medicinsk utveckling. När konceptet kvantkiralitet introducerades, var kopplingen mellan den kirala symmetrin och de kvantmekaniska tillstånden och operatorerna som utgör kvantkiralitet, inte trivial. Tidigare studier har visat att stängda spinnkedjor av ett udda antal spinn naturligt har kirala tillstånd som egentillstånd till en Hamiltonian beskrivande Heisenberg- och Dzyaloshinsky-Moriyainteraktioner. Att systemets symmetri stod i direkt relation till den kirala symmetrin av egentillstånden blev tidigt av intresse att undersöka. Syftet med denna kandidatuppsats är således att utforska en djupare förståelse till hur kvantkiralitet är en kiral symmetri samt utveckla en metod för hur kirala tillstånd kan drivas till att uppstå ur system som saknar den nödvändiga symmetrin. Resultaten visade att den diskretiserade sannolikhetsströmmen ger en god förklaring till varför de kirala tillstånden följer en kiral natur, men vidare efterforskning behövs för att kunna generalisera en djupare koppling mellan sannolikhetsströmmen och de kirala tillstånden hos spinnkedjor. Undersökningen indikerade också att det var möjligt att forcera en öppen spinnkedja till ett kiralt tillstånd, och till superpositioner därav, genom tidsutveckling. Metoden är fortfarande i sin tidiga utveckling och fysisk implementering samt tillämpningar väntar ännu på att upptäckas.