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Full-Text Articles in Engineering
Measurement Of Ultrafast Carrier Recombination Dynamics In Mid-Infrared Semiconductor Laser Material, William T. Cooley
Measurement Of Ultrafast Carrier Recombination Dynamics In Mid-Infrared Semiconductor Laser Material, William T. Cooley
Theses and Dissertations
Shockley-Read-Hall, radiative, and Auger recombination rates in mid-infrared laser structures are measured and reported using time resolved photoluminescence (TRPL) frequency upconversion. The mid-IR lasers studied were actual InAsSb/InAlAsSb multiple-quantum-well (MQW) diode lasers emitting near 3.3 micrometers which were previously characterized for laser performance. This effort extends the initial studies and reports on the carrier recombination dynamics. Shockley-Read-Hall, radiative and Auger recombination rates at low temperature (77 K) were measured and found to be ASRH ≈ 10 x 107sec-1, Brad ≈ 2 x 10-10 cm3sec-1 and CAuger < 10-29 cm6 …
Experimental Investigation Of Nonlinear Dynamics In Single Mode Semiconductor Laser Diodes With Phase Conjugate Feedback, Gordon T. Hengst
Experimental Investigation Of Nonlinear Dynamics In Single Mode Semiconductor Laser Diodes With Phase Conjugate Feedback, Gordon T. Hengst
Theses and Dissertations
The semiconductor laser diode offers a unique system to investigate nonlinear dynamics when optical feedback is applied. Although there is extensive research of laser diodes with optical feedback from normal dielectric mirrors, very little has been done experimentally to analyze the effects of degenerate phase conjugate feedback from a BaTiO3 crystal. This research experimentally investigated the dynamics of a single-mode laser diode with weak phase conjugate feedback using both the self-pumped and double phase conjugate geometries. The experimental results validated a mathematical model which numerically evaluates the Lang-Kobayahsi coupled differential equations. The model simulated the nonlinear behavior of a …
Thickness Effects On A Cracked Aluminum Plate With Composite Patch Repair, Joel J. Schubbe
Thickness Effects On A Cracked Aluminum Plate With Composite Patch Repair, Joel J. Schubbe
Theses and Dissertations
Post-repair fatigue crack growth was investigated in 3.175, 4.826, and 6.35 mm thick aluminum panels asymmetrically repaired with boron/epoxy composite patches bonded to the plates with FM73 sheet adhesive. Patches were uniaxial with patch to panel stiffness ratios ranging from 0.46 to 1.3. Experimental fatigue tests were carried out at 120 MPa, R=0.1, and 10 Hz (sinusoidal) to measure patched and unpatched face crack lengths, center crack opening displacements, and selected strains. Crack growth data was acquired using optical, eddy current, and post-test analysis methods. Crack growth rates were calculated using the incremental polynomial method. A three-layer Mindlin plate finite …
Investigation Of The Optical Properties Of Ordered Semiconductor Materials, Jack E. Mccrae Jr.
Investigation Of The Optical Properties Of Ordered Semiconductor Materials, Jack E. Mccrae Jr.
Theses and Dissertations
Optical studies have been conducted upon CdGeAs2 and ZnGeP2, two of the most promising semiconductors being developed for mid-infrared non-linear optics applications. These experiments included photoluminescence (PL) studies of both compounds as well as photoreflectance (PR) measurements upon CdGeAs2. In addition, Hall effect measurements were carried out upon CdGeAs2, to aid in interpretation of the optical data. PL was measured as a function of laser power, sample temperature, and crystal orientation for CdGeAs2. One broad weak peak near 0.38 eV, and another somewhat narrower and often far brighter peak near 0.57 …