This thesis represents the development of the first laser spectroscopy based trace-gas sensors with sensor characteristics which simultaneously satisfy low cost, handheld footprint, low power, and long term autonomous operation while still providing part-per-billion detection sensitivity and negligible interference to enable trace gas sensor networks ...

We describe what are to our knowledge the first measurements of the propagation of coherent, single-cycle pulses of terahertz radiation in a scattering medium. We measure the propagation constants for pulses in a dense collection of spherical scatterers, and compare to the predictions of the quasi-crystalline approximation. Even though the fractional ...

This thesis describes the study of two-dimensional photonic crystals slabs with terahertz time domain spectroscopy. In our study we first demonstrate the realization of planar photonic components to manipulate terahertz waves, and then characterize photonic crystals using terahertz pulses. Photonic crystal slabs at the scale of micrometers are first ...

In this dissertation work we have developed an ultracompact optically-detected terahertz resonance (ODTR) spectroscopy system, using quantum cascade lasers (QCLs). This system can be used for investigating various terahertz (THz) resonances in semiconductors. We use a THz QCL, of an appropriate frequency, operating in the close vicinity of the sample. ...

Propagation of single-cycle terahertz (THz) pulses through a random medium leads to dramatic amplitude and phase variations of the electric field because of multiple scattering. We present the first set of experiments that investigate the propagation of THz pulses through scattering media. The scattering of short pulses is a relevant subject to many ...

The intersection of silicon technology with the rapidly growing field of nanoplasmonics, provides a fertile ground for development of synergistic technologies. The optical and electrical properties of silicon are well understood and well characterized. In this thesis we explore the interactions of plasmonic nanostructures with both passive and active ...

In this dissertation we study the dynamic Franz-Keldysh effect (DFKE) in GaAs. We observe the salient features of DFKE viz., below bandgap absorption and oscillations above the band gap, in our experiments. We also report the first observation of a large photoinduced transparency which represents a novel coherent phenomenon based on the DFKE and ...

The 6.1-Angstrom (A) family of III-V semiconductors---InAs, GaSb, and AlSb and their alloys and heterostructures---has unique properties that may find application in next generation multi-functional semiconductor devices. In this project, we investigate intersubband transitions in 6.1-A quantum wells. The short-term objective is to explore ...

Terahertz time-domain spectroscopy (THz-TDS) offers a range of unique imaging modalities due to the broad bandwidth, sub-picosecond duration, and phase-sensitive detection of the THz pulses. Previous research in the THz field primarily focused on improving the optoelectronics and on qualitative investigation of suitable applications. In this thesis, ...

A novel methodology based on the scanning confocal microscope is presented which enables a general solution of the depth resolution problem in holography and other coherent imaging schemes. The method does not depend on a priori information about the object. Background and historical perspective are provided, as well as some review of the Rayleigh-Sommerfeld ...