Chapter 2 of this thesis will provide an overview on quantum cascade lasers qcls. Since their first demonstration in 2002, terahertz thz quantum cascade lasers qcls have proven to be one of the most reliable sources of this type of radiation. During my thesis work, i used the qcl simulation package developed by him for solving the wavefunctions in quantum cascade lasers. This thesis demonstrates qcl based spectroscopic techniques for multispecies detection, nonlinear. Unlike the main part of this thesis, the focus here was not on the development of highq, smallv. Title midinfrared ingaasinalas quantum cascade lasers. A periodic dielectric configuration with optimized and different periodicities in transverse and propagating directions is. An introduction is given explaining both the desire for a widely tunable, narrow bandwidth device working in the midinfrared, as well as detailing the ways in which. Design, analysis, and characterization of indirectlypumped terahertz quantum cascade lasers by seyed ghasem razavipour a thesis presented to the university of waterloo in ful llment of the thesis requirement for the degree of doctor of philosophy in electrical and computer engineering waterloo, ontario, canada, 20 c seyed ghasem razavipour 20.
Paircoil2 submit sequences to paircoil2 view supplementary data download paircoil2. However, it took more then two decades until the rst operating quantum cascade laser was manufactured by j. Many investigations about these lasers are being done both experimentally and theoretically and part of the experimental work is mainly concerned with the confirmation of theoretical predictions. Infrared laser absorption spectroscopy provides a powerful tool for probing physical and chemical properties of highexplosive detonations. Most of these devices are grown by molecular beam epitaxy mbe except for some of those grown by metalorganic chemical vapor deposition mocvd. Publications quantum and nonlinear optoelectronics group. He was inspirational in making me come up with the idea of working with distributed feedback quantum cascade laser. This greatly improves the efficiency of the devices at these wavelengths, because it is difficult to find. A quantum cascade laser qcl is a semiconductor laser operating in the mid to long infrared and terahertz regime. Photons are emitted via electronic intersubband transitions that. Coupled with tunable diode laser tdl spectroscopy, a single instrument is now able to broaden insight and monitor both the near and midinfrared range of spectroscopic light. Challenges and developments, which are the subject of. It is a bipolar device, in which the optical transitions involve. Quantum cascade lasers qcls are high power, narrow linewidth midir lasers that are increasingly popular for trace gas sensing and nonlinear spectroscopy.
Security applications usingbroadlyusing broadly tunable. This makes it possible to direct the emitted light into a collimated beam, and allows a laser resonator to be built such that light can be coupled back into the gain medium two types of optical waveguides are in common use. Quantum cascade lasers have recently gained considerable attention for their capability to emit infrared radiation in a broad infrared spectral region, very compact dimensions, and high optical powerefficiency. Qcl and icl have similar structures and working principles. Emersons quantum cascade laser technology offers fast, high resolution spectroscopy to detect and identify a range of molecules in the midinfrared wavelength range. Novel waveguides for terahertz quantum cascade lasers. Optical dielectric nanoantenna for quantum cascade laser. As a result of this work midinfrared quantum cascade laser have been successfully. An electron in the upper laser level relaxes down to the lower laser level to emit photons of a. Pdf characterization of midinfrared quantum cascade lasers. A thesis presented to the university of waterloo in fulfillment. A quantum cascade laser can be made from a periodic multiple quantum well mqw structure as in figure 1.
Williams submitted to the department of electrical engineering and computer science on august 22, 2003, in partial ful. Emmy noether research group, institute for nanoelectronics master thesis diplomarbeit. Novel waveguides for terahertz quantum cascade lasers doctoral thesis. It is built out of quantum semiconductor structures that were grown by molecular beam epitaxy and designed by band structure engineering.
Cw quantum cascade lasers, which will be operated in a continuous emission mode. Today quantum cascade lasers in the range of 4 to 10 m wavelength operate routinely continuouswave at room. Focus lies on the quantitative modeling of the gain when the systems are exposed to strong laser. This thesis investigates the material growth of near. Theoretical and experimental studies on temperaturedriven scattering. With up to wattlevel room temperature emission over a broad swath of midinfrared wavelengths, these tiny semiconductor devices enable a variety of applications and technologies such as ultrasensitive systems for detecting trace molecules in the vapor phase. Quantum cascade qc lasers are todays most capable midinfrared light sources. The work described in this thesis focuses on development of qcls suitable for selective gas sensing applications.
The focus of this thesis is the development of compact, roomtemperature terahertz sources based on quantum cascade lasers qcl and quantum well technology. The quantum cascade laser qcl is a solid state device capable of. This thesis presents the concept and modeling of a dielectricpatterned nanoantenna integrated with a quantum cascade laser qcl device to tailor the radiation beam and provide directive emission characteristic. O guz gulserenadvisor ceyhun bulutay mehmet emre ta. In this thesis, two novel upper quantumstate designs. A common feature of these two kinds of cascade lasers is electron recycling, which means that one electron can produce multiple photons. Trace gas spectrometry using quantum cascade lasers. In summary, the design, optimization, fabrication and characterization of the midinfrared quantum cascade lasers. The first step in processing quantum cascade gain material to make a useful lightemitting device is to confine the gain medium in an optical waveguide. Simulation of quantum cascade lasers masters thesis, bachelors thesis starting immediately motivation the quantum cascade laser qcl is a novel type of semiconductor laser. The steps consist of coupled quantum wells in which population.
Applications of a midir quantum cascade laser in gas sensing research thesis by muhammad bilal sajid in partial fulfillment of the requirements for the degree of doctor of philosophy king abdullah university of science and technology thuwal, kingdom of saudi arabia may 2015. Design, analysis, and characterization of indirectly. Modeling quantum cascade lasers the challenge of infrared. In 1996, aboveroomtemperature operation in pulsed mode was achieved, and the longwavelength range was extended already to 11 m faist et al. Monolithic tuneable quantum cascade lasers enlighten. Materials used, as well as growth methods, are also described.
A bench mounted two channel quantum cascade laser absorption spectrometer. David burghoff, ningren han, filippos kapsalidis, nathan henry, mattias beck, jacob khurgin, jerome faist, qing hu, optomechanical control of quantum cascade laser frequency combs, spie photonics west 2019, san francisco, ca, februrary 2019 david burghoff, terahertz quantum cascade laser frequency combs, 14th international conference on midir. Applications of a midir quantum cascade laser in gas. Due to the subwavelength transverse dimensions of the metalmetal waveguide, however, obtaining a directive beam pattern and efficient outcoupling of thz power is nontrivial. This is the first such work that uses a qcl in conjunction with the cw.
We certify that we have read this thesis and that in our opinion it is fully adequate, in scope and in. Advances have been made in increasing maximum operating temperature, shaping the beam and tuning the. Quantum cascade laser as an example by hamed abbasian february 2018 we certify that we have read this thesis and that in our opinion it is fully adequate, in scope and in quality, as a thesis for the degree of master of science. Quantum cascade lasers for midinfrared chemical sensing a. A new concept of constant power laser current source has been proposed and designed in a circuit. I, richard walker, declare that this thesis titled, quantum cascade laser spectroscopy. Quantum cascade lasers qcls have rapidly advanced to a leading position among infrared light sources, and are being used in a number of chemical sensing and spectroscopic applications. This thesis research details the development of a quantum cascade laser qcl based continuouswave cavity ringdown spectrometer cwcrds coupled to an oven supersonic expansion source. The thz quantum cascade laser project would not have started without success in growing and fabricating thz qcls by the photonics ceneter umass lowell group. This thesis details the development of quantum cascade lasers.
A broadly tunable sweptwavelength external cavity quantum cascade laser operating in the midwave infrared mwir spectral region is used to measure transmission through explosive fireballs generated from 14 g charges of 4 different explosive types. Terahertz quantumcascade transmissionline metamaterials. Qcls are semiconductor lasers that operate with high power at midinfrared midir and thz frequencies. A quantum cascade laserbased sensor for ambient air monitoring is presented and five gases, affecting the air quality, can be quantified. The light sources are selected to measure co, no, no2. Increasing continuous wave optical power is one of the main research directions in the field. This thesis is concerned with the design, fabrication and characterisation of monolithic tuneable quantum cascade lasers qcls, which are suitable for tuneable diode laser based absorption spectroscopy and polarisation dependent spectroscopy in the midinfrared wavelength range. Quantum cascade laser spectroscopy ora oxford university. They have established themselves as the laser of choice for spectroscopic gas sensing in the midwavelength infrared 38. Nonlinear dynamics of quantum cascade laser in ring cavity. Characterization and theoretical study of midinfrared quantum. Quantum cascade lasers qcls are capable of high power, tunable wavelength and single mode emission at room temperature in the midinfrared wavelength region. The icl is a combination of traditional diode laser and quantum cascade laser qcl.
Analysis of diffraction grating induced distributed. This thesis presents work examining the characteristics and applicability of quantum cascade lasers. Development of quantum cascade lasers for gas sensing. These capabilities make them perfect light sources for laser based gas spectroscopy. A semiconductor injection laser that differs in a fundamental way from diode lasers has been demonstrated. This thesis will present the results of experimental work carried out during studies on the detection of gases and the nonlinear optical e. An overview is prefaced, including a brief description of their beginnings and operating basics.
This thesis focuses on the design, fabrication and measurement of the surfaceemitting distributed feedback terahertz quantumcascade phaselocked laser. Quantitative modeling of gain in quantum cascade lasers under operational intensities abstract this thesis adresses modeling of quantum cascade lasers using nonequilibrium greens functions. This thesis details the development of quantum cascade lasers qcls that operate in the terahertz with photon energies below the semiconductor reststrahlen band. The system soft bl t ti id tifi tiftware enables automatic identification. This thesis reports the demonstration of a onedimensional waveguide for terahertz quantumcascade lasers that acts as a leakywave antenna and tailors laser radiation in. Summarizing, the applications of these structures cover a broad range, including spectroscopy. This thesis presents the first comprehensive analysis of quantum cascade laser nonlinear dynamics and includes the first observation of a temporal chaotic behavior in quantum cascade lasers. Within each period, there are energy states for injection, depletion, and two laser levels.
All investigations and device development work were carried out using the qcl structure based on straincompensated. It also provides the first analysis of optical instabilities in the midinfrared range. Multicomponent gas analysis using broadband quantum cascade laser spectroscopy we present a broadband quantum cascade laserbased spectroscopic system covering the region between 850 and 1250 cm1. Xifeng qian, neelima chandrayan, krongtip termkoa, dr. Unlike the main part of this thesis, the focus here was not. Here, the optical transitions occur between quantized energy levels within the conduction band, rather than between the conduction and valence bands see fig. Characterization and theoretical study of midinfrared. A straightforward approach to increasing optical power in the pulsed regime is to increase. Nonlinear dynamics of quantum cascade laser in ring cavity a thesis submitted to the faculty of the graduate school of the university of minnesota by hadi madanian in partial fulfillment of the requirements for the degree of. Characterization of highexplosive detonations using.
Cascade lasers includes quantum cascade lasers qcls and interband cascade lasers icls. Pulsed quantum cascade lasers, which will be operated in a short pulse mode with a typical pulse duration of 150ns. Nonlinear photonics in midinfrared quantum cascade lasers. Quantum cascade lasers qcls are semiconductor devices that, currently, have been observed to emit radiation from 2. The quantum cascade laser qcl is a solid state source of coherent radiation in the tera hertz and. A novel design of high peak power midinfrared quantum cascade lasers has been modeled, implemented and characterized. Introduction last year marked the 20th anniversary of the invention and demonstration of the quantum cascade laser qcl at bell laboratories 1.
Electrons streaming down a potential staircase sequentially emit photons at the steps. Room temperature operation of quantum cascade lasers. Modeling of semiconductor devices based on quantum wells. High power continuous wave quantum cascade lasers with.
The possibility of developing ganbased qcls is also shown. Quantum cascade lasers in the midinfrared white rose. Its robust multipass cavity ensures a constant interaction length. Highpower and narrowlinewidth optimizations of mid. Quantitative modeling of gain in quantum cascade lasers. The thesis work was financially supported by the european.
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