OPTICAL FACET COATINGS FOR TRANSISTOR-INJECTED QUANTUM CASCADE LASER

Perry, Elise

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https://hdl.handle.net/2142/125070 Copy

Description

Title

OPTICAL FACET COATINGS FOR TRANSISTOR-INJECTED QUANTUM CASCADE LASER

Author(s)

Perry, Elise

Issue Date

2020-05-01

Keyword(s)

Quantum cascade lasers (QCLs) , high-reflectivity (HR) optical coating

Abstract

Quantum cascade lasers (QCLs) are diode lasers that use intersubband transitions to emit in the mid-infrared spectral regime. The mid-infrared regime is commonly used for military applications such as thermal imaging and missile deterrent systems as well as in environmental sensing such as composition spectroscopy and pollutant detection. However, conventional QCLs are diode devices that limit the operation of the device to bias limits that align the intersubband transition states. The transistor-injected quantum-cascade laser (TI-QCL) is a three-terminal laser that uniquely provides independent injection current control and alignment of the intersubband transition states. This presents a widely tunable mid-IR emitter that can be used in a wide variety of applications. To improve the mirror reflectivity of the TI-QCL, voltage-tuned distributed feedback (DFB) gratings can be designed and the spectral reflectivity can be aligned to the emission of the TI-QCL. This senior thesis encompasses the theoretical evaluation of a high-reflectivity (HR) optical coating for the distributed feedback grating that can be implemented into the TI-QCL for wavelength ranges corresponding to its emission. This research has led to the design of a hybrid metal-dielectric coating with thicknesses specified in order to maximize reflectivity while balancing the constraints of fabrication.

Type of Resource

text

Language

eng

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