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Advisory Committee Chair

Renato P Camata

Document Type

Dissertation

Date of Award

2010

Degree Name by School

Doctor of Philosophy (PhD) College of Arts and Sciences

Abstract

Transition metal doped II-VI semiconductor materials features excellent spectroscopic and lasing characteristics in the middle infrared (mid-IR). Among this class of laser material, the most impressive results have been obtained from chromium-doped zinc selenide (Cr2+:ZnSe) crystals. To date, Cr2+:ZnSe materials are arguably the best choice of laser gain material for the advancements of high power mid-IR lasers broadly tunable over the 2-3 μm spectral range. The dissertation objectives are to demonstrate technological advancements in the development Cr2+:ZnSe thin films by pulsed laser deposition (PLD) thus establishing a viable route for the synthesis of mid-IR laser gain media based on Cr2+:ZnSe thin films. The first major objective of this dissertation is the realization of high optical quality Cr2+:ZnSe thin films with effective control over the Cr2+ dopant concentration and uniformity. Accomplishing this objective could only be attained through the availability of high quality Cr-doped ZnSe ablation targets. Manufacturing procedures for ablation targets fabricated in-house were perfected and used to produce Cr2+ concentration variations in films deposited to less than 15% in samples with Cr2+ concentration ~1019 ions/cm3. PLD deposition parameters were optimized that resulted in formation of high optical quality Cr2+:ZnSe films that were used to consistently exhibit room temperature photoluminescence (PL) measurements over the 2-3 μm mid-IR spectral range. This was the first demonstration of PL measurements from PLD grown Cr2+:ZnSe thin films. The second objective was to demonstrate mid-IR lasing from PLD grown Cr2+:ZnSe based thin film structures. The first demonstration of 2.63 μm mid-IR lasing in a Cr2+:ZnSe thin film planar waveguide structure developed using PLD is presented in this dissertation research. Mid-IR lasing oscillation within a planar waveguide, achieved through the deposition of a highly doped Cr2+:ZnSe film on sapphire substrate, was obtained at room temperature under gain-switched optical excitation. Highly doped Cr2+:ZnSe thin films were also used to demonstrate passive Q-switching of Er-doped YAG laser operating at 1.645 μm. The third objective was to develop Cr2+:ZnSe-based thin film electroluminescent structures by PLD. Significant progress was made in the development of thin film structure designs that shows promising results for the impending successful demonstration of mid-IR electroluminescence.

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