One of the key advances in photonic technology in recent decades was the development of a new type of diode lasers emitting in the visible and infrared region. These vertical cavity surface-emitting lasers (VCSELs) emerged from a laboratory curiosity in 1977 [13] to an object of industrial mass production [14] and are currently used in many applications. The applications include communication, printing, and absorption spectroscopy [15]. Their rise in credibility has largely been motivated by the rapid evolution of their performance, the more sweeping recognition of their compatibility with low-cost wafer-scale fabrication, and their possible formation into specific arrays with no change in the fabrication procedure. Various applications such as advanced chemical sensors and high-density optical storage require coherent and small-size ultraviolet-emitting devices (below 400nm). Therefore, to extend the VCSEL emission to the ultraviolet (UV) region, intensive efforts have been made in the VCSEL technology. However, the achievement of such UV VCSEL is very challenging because of the various limitations and issues. The issues noticeably include the carrier injection, optical confinement, and highly reflective distributed Bragg reflectors (DBR) structures with a broad bandwidth operating in the UV region [16]. In this context, motivated by the reported large refractive index induced by boron incorporation [7], we propose to introduce the boron-based material systems (BAlGaN) as an innovative solution to address some of the encountered difficulties. The objective of the proposed research is to investigate and optimize new wide-bandgap BAlGaN material systems and illustrate their incorporation into the building blocks of vertical cavity surface-emitting laser structures for operation in the UV spectral range (<400nm). Toward this goal, we have focused our research activities in three main directions. The first direction is devoted to the simulation of DBRs reflectivity by taking into consideration the experimental refractive indexes. Once the materials needed in the different components of the VCSEL are well defined, the second direction lies in the achievement of growth conditions optimization and characterization of the new wide-bandgap BAlGaN material systems. The study has led to the structural and morphological quality improvement of (B,Al,Ga)N materials. Unique optical properties of the BGaN and BAlN materials were also demonstrated. Upon demonstrating the materials' promising optical characteristics, the final direction consists of the epitaxial growth and characterization of the highly reflective DBRs and active region of the UV VCSEL structure.

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Electrical and Computer Engineering." Includes bibliographical references (p. 256-264).

Thesis (M.S.) in Electrical Engineering--University of Maine, 2009. / Includes vita. Includes bibliographical references (leaves 63-65).

Thesis (Ph.D.)--Kent State University, 2009. / Title from PDF t.p. (viewed Feb 25, 2010). Advisor: Oleg Lavrentovich. Keywords: electro-optical applications of liquid crystals, beam steering devices, polarization rotator, negative refraction, electrically tunable lens, colloidal dynamics, bidirectional motion of colloidal particles in liquid crystals controlled by backflow. Includes bibliographical references.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references (leaves 80-82). Also available in electronic version. Access restricted to campus users.

Thesis (Ph. D.)--Rutgers University, 2008. / "Graduate Program in Chemistry and Chemical Biology." Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Supervisor: Archie L. Holmes, Jr. Vita. Includes bibliographical references. Also available from UMI.

With the increased requirement on the ultrafast measurement technology, how to resolve the spectral dynamics has the top priority on the research list, since spectrum is an essential carrier for most of the physical or chemical phenomena. According to the Nyquist-Shannon sampling theorem, if a function 𝑥(𝑡) contains no frequencies higher than 𝐵 Hz, it is completely determined by giving its ordinates at a series of points spaced 1/(2𝐵) seconds apart. Since most of the conventional optical spectrum analyzers (OSAs) are operated with the sampling rate (or frame rate) of 5 Hz, it results in the resolvable bandwidth of the spectrum dynamic is less than 2.5 Hz. With the development of the space-time duality, the analogy transforms the conventional spatial dimension into the time axis, and the well-known spatial models inspire us in performing their counterparts in the time domain. As one of the most powerful tools in achieving ultrafast time axis information, time-lens plays a more and more important role in the single-pixel imaging system. By fully analyzing the diploma of the previous optical spectrum resolving mechanisms, in this thesis, for the first time, we raised up the concept the parametric spectrotemporal analyzer (PASTA), which is based on the time-lens focusing mechanism. Here the spectrum resolving frame rate is increased to 100 MHz, then the observable spectrum dynamic bandwidth could be 50 MHz, which is sufficient for most of the ultrafast phenomena. In the PASTA system, the time-lenses are implemented with the fiber optical parametric amplifier (FOPA) based parametric mixer, which provides higher conversion efficiency and repetition rate. On the other hand, the dispersion based dispersive Fourier transformation (DFT) technology generates the swept-pump for the FOPA, as well as the temporal dispersion medium. This research in this thesis is a fundamental study on the newly PASTA system, from its origin and the theoretical background, to the implementation techniques and operation performances. From its implementation, its principles are strongly related with the combination of the dispersion and the Kerr nonlinear effects, especially the swept-pump FOPA in the time-lens part. The DFT technique, in generating the fast swept-source, has also find its applications in the ultrafast serial time-encoded amplified microscopy (STEAM) and swept-source optical coherence tomography (SS-OCT) systems. Finally, the single-lens PASTA prototype is capable of resolving 5-nm wavelength range with 0.03-nm resolution under 100-MHz frame rate. Moreover, besides the singlelens PASTA, the telescope/wide-angle configurations have also been investigated experimentally to achieve the spectrum zoom in/out ratio as high as 17 times, here we have obtained the sharpest resolution of 5 pm (<1 GHz) with the telescope configuration, and the widest observation range of 9 nm with the wide-angle configuration. My research efforts presented in this thesis mainly leverage the ultrafast characteristics of the time-lens system, from theory to implementation, and achieve the real-time optical spectrum analysis – the PASTA system. PASTA is not only essential in observing some non-repetitive ultrafast phenomena, but also provides a potential solution for the frequency to time transformation in some ultrafast bio-medical imaging systems. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

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