Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 13 of 13 for “"Quantum Cascade Laser (QCL)"”.
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Towards terahertz dual-comb spectroscopy based on quantum cascade lasers
In this thesis, terahertz (THz) laser frequency combs are improved and THz dual-comb spectroscopy method is demonstrated. To achieve better performance of THz quantum cascade laser (QCL) frequency combs, several broadband homogeneous and heterogeneous gain media are characterized, and corresponding …
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Development of Broadband Semiconductor Laser Frequency Combs
Quantum Cascade Laser (QCL) is a compact, mature and flexible coherent radiation source in both terahertz (THz) and mid-infrared (midIR) frequency range. Many molecules have rotational-vibrational absorption bands in midIR, making QCL-based dual comb spectroscopy (DCS) systems the ideal tool for …
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Development of terahertz quantum-cascade lasers
… remarkable development of mid-infrared ( ... ) quantum-cascade lasers (QCLs) in the past decade, this thesis describes the development of electrically-pumped terahertz quantum-cascade lasers in GaAs/AlsGal_.As heterostructures that span a spectral range of 1.59 - 5.0 THz ( ... ). A …
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Highly tunable room temperature quantum cascade lasers
… was conducted into the feasibility of novel Quantum Cascade Laser (QCL) technology to replace Optical Parametric Oscillator based light sources in real-time video-rate gas imaging systems. Such a laser must produce pulses of >5ns in duration at a repetition rate of at least 5kHz with peak …
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Terahertz imaging and quantum cascade laser based devices
… demonstrated using recently developed terahertz quantum-cascade laser (QCL) sources, along with commercial, focal plane array thermal detectors. The system uses a high power (48 mW) 4.3-THz QCL, which is also used to characterize the focal plane array, resulting in a noise equivalent power (NEP) …
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Discrete-frequency infrared imaging with a quantum cascade laser and diffuse optical Raman tomography: methods toward improving clinically relevant label-free chemical contrast
… with significant potential include the use of quantum cascade laser technology for mid-infrared spectral imaging and diffuse Raman tomography for three dimensional chemical analysis. In this thesis, we constructed and evaluated two analytical instruments which represent the first steps toward …
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New modeling of compact, high-efficiency, and widely-tunable gas-phase terahertz lasers
… sources. Optically pumped far-infrared (OPFIR) lasers were one of the most powerful continuous-wave terahertz sources. However, such lasers have long been thought to have intrinsically low efficiency, not tunable in frequency, and large sizes. In this thesis, we introduce a compact, …
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Long-wave infrared frequency combs based on quantum cascade lasers
Ever since the invention of quantum cascade laser (QCL), the performance and the flexibility in design has made it a desirable source for a wide range of applications, such as trace-chemical sensing, health monitoring, frequency metrology, noninvasive imgaing and infrared countermeasures. The LWIR …
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Shock Tube and Mid-IR Laser Absorption Study of Combustion Kinetics
… fuels. Specifically, a shock tube and direct laser absorption systems are used to investigate the ignition and pyrolysis processes of target fuels. The research problem is motivated by concern about climate change and diminishing fossil fuels. There is a need to develop advanced combustion …
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High-resolution infrared spectroscopy of large molecules and water clusters using quantum cascade lasers
… water clusters which have been obtained using a quantum cascade laser (QCL) based infrared spectrometer coupled to a supersonic expansion source. The spectrometer operates near 8.5 μm and has been developed for the purpose of obtaining a high-resolution gas phase spectrum of C60 for use in …
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Development of a quantum cascade laser based spectrometer for high-resolution spectroscopy of gas phase C60
This thesis research details the development of a quantum cascade laser (QCL) based continuous-wave cavity ringdown spectrometer (cw-CRDS) coupled to an oven supersonic expansion source. This is the first such work that uses a QCL in conjunction with the cw-CRD technique and a supersonic expansion …
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Semiconductor quantum dots for mid-IR light emission
… structure, advantages and disadvantages of quantum cascade laser (QCL), interband cascade laser and type-I quantum well lasers, which together cover the wavelength range from 2 μm to 11 μm. Then, in the last part of chapter 1, we provide an introduction to quantum dots and a discussion as to …
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The design and fabrication of an inp-based transistor-injected quantum cascade laser
… practical solutions to these problems. While quantum cascade lasers (QCLs) present one appealing solution for these infrared sources, inherent limitations related to efficiency and operational control leave room for improvement. The transistor-injected quantum cascade laser (TI-QCL) presents a …