This study explored how six Arab EFL teachers constructed meanings of reflection, and how these meanings informed their teaching practice. The purpose of this research was to better understand reflective practice in teacher education. Dewey (1933), Schön (1983, 1987) and van Manen’s (1977) theories on reflective practice guided this study. A symbolic interaction theoretical and methodological framework (Denzin, 1978; Prus, 1996) was applied. The data were collected from teacher interviews, reflection journals and classroom observations. Five specific themes emerged from the data and were categorised within the symbolic interaction social processes of (1) acquiring perspectives, (2) achieving individuality, (3) experiencing relationships, (4) situating the act, and (5) the act of reflection (Prus, 1996). In addition, eleven sub-themes were derived from the data which illuminated how the teachers interpreted and practised reflection. The sub-themes included: (1) defining reflection, (2) questioning as reflection, (3) opportunities for reflection, (4) defining reflection from self / significant others, (5) looking back on action, (6) reflection is based on personal beliefs and educational theory, (7) encountering peers / cooperating teachers, (8) self-reflections, (9) verbal reflections, (10) written reflections, and (11) content of reflection. The findings revealed that teachers possessed a general understanding of reflection and practised technical and interpretive levels of reflection in different contexts. Engaging in reflective practice activities encouraged the teachers to question their own beliefs and theories. The study provided evidence showing that reflection is a key element of teacher development. Reflective thinking is a vehicle that can help teachers to progress from a level where they are mainly guided by intuition to a level where their actions are guided by reflection and self-inquiry. The study has implications for the ways in which teachers learn about reflection, and I do hope that teacher educators will find it useful.

Quantum cascade lasers (QCL) are semiconductor lasers that emit radiation in the mid-infrared to the terahertz (THz) range. External cavity quantum cascade lasers are broadly tunable mid-infrared and even THz laser sources that have a wide variety of applications in spectroscopy, sensing, imaging and other areas. Anti-reflection (AR) coatings, when applied on the laser facet reduce parasitic lasing, increase spectrum purity and tuning range, are crucial for good performance of external cavity systems. This report describes the process of determining the thickness of a double layer AR coating, applying the coatings to a quantum cascade laser and testing its reflectivity in the mid-infrared range. We determined the thickness of each layer of the AR coatings by building a propagation matrix model using Mathematica. We applied the coatings of Al2O3 and ZnSe using an Electron Beam Physical Vapor Deposition and a Sputtering Deposition system. Finally we tested the reflectivity of the laser by measuring a change in threshold current. The initial reflectivity of 30% was reduced to 7.7% with the addition of the AR coatings. / text

published_or_final_version / Computer Science / Doctoral / Doctor of Philosophy

Inaug.-diss.--Berlin. / Lebenslauf.

Thesis (Ph. D.)--Johns Hopkins University, 1915. / Biography. "Reprinted from the Physical review, n.s., vol. VII., no. 1, January, 1916."

Thesis (Ph. D.)--Johns Hopkins University, 1915. / Biography. "Reprinted from the Physical review, n.s., vol. VII., no. 1, January, 1916."

Thesis (Ph. D.)--Columbia University. / Reprinted from the Astrophysical journal, vol. xxvi, no. 4, November, 1907.

Inaug.-diss.--Berlin. / Lebenslauf.

Thesis (Ph. D.)--University of Iowa, 1920. / Cover title. Reprinted from the Journal of the Optical Society of America and Review of scientific instruments, vol. VII, no. 8, August, 1923, and vol. VII, no. 9, September, 1923.

Inaug.-diss.--Kiel. / Vita.