This dissertation presents nonlinear terahertz (THz) properties of carbon nanomaterials investigated by time-resolved high-field THz spectroscopy. In order to determine THz characteristics of nanomaterials, we performed THz power spectrum measurement, THz raster imaging, THz time-domain spectroscopy (THz-TDS) and time-resolved pump-probe experiment on two different types of single layer graphene and...
To obtain a mechanistic understanding of the chemical processes, techniques that offer a frame-by-frame visualization of molecular structure during a reaction are of vital importance. Numerous efforts and advances have been made in order to acquire such vivid molecular “movies”, especially in the electronic excited state. Ultrafast molecular spectroscopy method...
In this work we apply the finite temperature formulation of quantum
statistical mechanics to an analysis of the de Haas-van Alphen effect
in the quantum limit. A new expression is derived for the differential
magnetic susceptibility which clearly shows the individual contributions
of zero-temperature and non-zero temperature terms.
Interactions have...
In this thesis I studied several THz components that can be used for potential THz
technology. THz waves were generated in nonlinear medium via optical rectification
of femtosecond optical pulses. Utilizing the phase matching condition between the
optical and THz waves in a ZnTe crystal, single-cycle broad-band THz pulses were...
This work comprises two main parts: creating and shaping narrowband, pulsed THz radiation in a table-top optical setup; and applying THz pulses to semiconductor nanostructures to study electron dynamics.
I developed a scheme to shape the THz output of a fanned-out periodically poled lithium niobate (PPLN) crystal. The pulses are...
The photophysical properties of two-dimensional (2D) layered van der Waals (vdW) materials, and their heterostructures are manifestly distinct from crystalline bulk materials. Recently, the discovery of new 2D vdW materials and strongly-bound interlayer excitons in these materials has created a new branch in nanoscience. As such, there are a number...
This dissertation is an exploration of the material response to Terahertz (THz) radiation. Specifically we will explore the ultrafast electron dynamics in the nonperturbative regime in semiconductors that have been patterned with nanoantenna arrays using broadband, high intensity, THz radiation. Three main semiconductor materials will be studied in this work....
The utility of high-throughput, computational screening has become an invaluable asset to the field of materials science. In the hierarchy of computational methods, the most accurate methods are often the most computationally expensive. However, as both the efficiency and fidelity of numerical techniques advance, high-quality screening of large materials datasets...
I led a collaborative project involving a search for an evidence of a gravitational wave background (GWB) with all the spatial correlations allowed by general metric theories of gravity using NANOGrav’s 12.5 year data set. The search found no substantial evidence in favor of the existence of such correlations.
The...