Author

Sara Kacmoli

Publication Date

2017-5

Document Type

Honors Thesis

Degree Name

Bachelor of Science

Department

Engineering

Advisors

Claire F. Gmachl

Keywords

Quantum cascade lasers, Spontaneous emission, Superluminescence, Active region design, Spiral Cavity, Optical choherence tomography, Mid-infrared emission, Chemical sensing, Luminescence, Lasers in medicine, Infrared radiation, Chemical detectors

Abstract

In this work quantum cascade devices with novel intrinsic quantum structures are designed and characterized. The novel intrinsic design presented is aimed at maximizing the dipole matrix element (31.5 ˚A) while suppressing population inversion by decreasing the upper-state lifetime of the electrons (1.25 ps) compared to previous designs. It is expected that these features will contribute to the increase of power from spontaneous emission. Both active and injector region doping is employed in order to achieve a broad spectrum. Devices with a different quantum design are characterized; these devices also aim to maximize the dipole matrix element with an extended active region that is doped for low coherence. Via preliminary measurements, superluminescence at 8 μm is observed. The power achieved without optimizing the position of the devices is on the order of 1 mW. After optimization the power is expected to increase to at least four times its current value. While these measurements reveal a lower coherence length in the IR doped devices, further characterization is needed to verify the relationship between doped regions and coherence length.

Language

English

Comments

v, 42 pages : color illustrations. Includes bibliographical references (pages 41-42)

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