A. M. Andrews
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View article: Integrated Metallic Hollow Waveguides with Terahertz Quantum Cascade Lasers
Integrated Metallic Hollow Waveguides with Terahertz Quantum Cascade Lasers Open
Scaling down the size of terahertz optical systems is a challenging task because of the long wavelengths involved. We have addressed the problem with on-chip integration of terahertz quantum cascade laser (THz QCL) devices with subwaveleng…
View article: Interband response of type-II quantum cascade detectors [Invited]
Interband response of type-II quantum cascade detectors [Invited] Open
Quantum cascade detectors (QCDs) are room-temperature photovoltaic infrared devices based on intersubband transitions. In this work, we expand the mid-infrared QCD functionality by utilizing the interband (IB) transitions in the extractor …
View article: Refined Epitaxial Growth of YbRh <sub>2</sub> Si <sub>2</sub> Thin Films
Refined Epitaxial Growth of YbRh <sub>2</sub> Si <sub>2</sub> Thin Films Open
Epitaxial thin films of the heavy fermion compound YbRh 2 Si 2 have opened new possibilities in the investigation of the enigmatic strange metal state, including terahertz transmission spectroscopy and shot noise. For experiments at lower …
View article: Tunable comb operation in terahertz quantum cascade ring lasers
Tunable comb operation in terahertz quantum cascade ring lasers Open
We demonstrate a versatile and compact approach to generate and control terahertz frequency combs by applying radio frequency modulation to a ring-shaped quantum cascade laser. By harmonically driving the device well above threshold, we in…
View article: Micro-mirror aided mid-infrared plasmonic beam combiner monolithically integrated with quantum cascade lasers and detectors
Micro-mirror aided mid-infrared plasmonic beam combiner monolithically integrated with quantum cascade lasers and detectors Open
The development of novel mid-infrared (MIR) devices and systems is crucial for addressing applications in biomedical analysis, chemical reaction-monitoring, or high-bitrate free-space telecommunication. Combining multiple functional elemen…
View article: Water vapor quantification in raw product gas by THz quantum cascade laser
Water vapor quantification in raw product gas by THz quantum cascade laser Open
Online quantification of water vapor in hot and complex gases, like raw product gas from biomass gasification, is essential for process understanding and control. The complex nature of these gases presents many challenges, e.g., band overl…
View article: Compact vertical emitting ring interband cascade lasers for isotope-resolved CO2 sensing
Compact vertical emitting ring interband cascade lasers for isotope-resolved CO2 sensing Open
We present a compact vertically emitting ring interband cascade laser (ICL) with low power consumption and the possibility for seamless integration into various CO2 sensing applications. Our devices exhibit desirable performance characteri…
View article: Coupled terahertz quantum cascade wire lasers
Coupled terahertz quantum cascade wire lasers Open
We present mutual optical coupling in terahertz (THz) quantum cascade wire laser arrays that are flip-chip bonded to a dielectric substrate. The mounting substrate is patterned for individual electrical contacting of each wire laser of the…
View article: Experimental investigation on the effect of temperature on the frequency limit of GaAs-AlGaAs and AlGaN-GaN 2DEG Hall-effect sensors
Experimental investigation on the effect of temperature on the frequency limit of GaAs-AlGaAs and AlGaN-GaN 2DEG Hall-effect sensors Open
This follow-on work investigates the effect of temperature on the frequency limit of 2-dimensional electron gas (2DEG) Hall-effect sensors.
View article: Design and performance of GaSb-based quantum cascade detectors
Design and performance of GaSb-based quantum cascade detectors Open
InAs/AlSb quantum cascade detectors (QCDs) grown strain-balanced on GaSb substrates are presented. This material system offers intrinsic performance-improving properties, like a low effective electron mass of the well material of 0.026 m 0…
View article: A monolithic frequency comb platform based on interband cascade lasers and detectors
A monolithic frequency comb platform based on interband cascade lasers and detectors Open
Optical frequency combs enable all-solid-state spectrometers that will trigger a breakthrough in miniaturization and on-chip integration of mid-infrared sensing technology. Interband cascade lasers (ICLs) are an ideal candidate for practic…
View article: Shot noise in a strange metal
Shot noise in a strange metal Open
S trange-metal behavior has been observed in materials ranging from high-temperature superconductors to heavy fermion metals. In conventional metals, current is carried by quasiparticles; although it has been suggested that quasiparticles …
View article: Effect of geometry on the frequency limit of GaAs/AlGaAs 2-Dimensional Electron Gas (2DEG) Hall effect sensors
Effect of geometry on the frequency limit of GaAs/AlGaAs 2-Dimensional Electron Gas (2DEG) Hall effect sensors Open
In this work, we experimentally investigate the frequency limit of Hall effect sensor designs based on a 2 dimensional electron gas (2DEG) gallium arsenide/aluminum gallium arsenide (GaAs/AlGaAs) heterostructure. The frequency limit is mea…
View article: Beyond Karl Fischer titration: a monolithic quantum cascade sensor for monitoring residual water concentration in solvents
Beyond Karl Fischer titration: a monolithic quantum cascade sensor for monitoring residual water concentration in solvents Open
A sensitive and selective monolithic mid-IR lab-on-a-chip for real-time analysis of water-residuals in solvents with comparable LOD to Karl–Fischer titration.
View article: Ultrabroadband Heterogeneous THz Quantum Cascade Laser
Ultrabroadband Heterogeneous THz Quantum Cascade Laser Open
Broadband emission in the terahertz spectral region is a prerequisite for applications such as spectroscopy or white light sources. Appropriate signal powers and a compact design are advantageous for this use. A technology which meets thes…
View article: High-responsivity operation of quantum cascade detectors at 9 µm
High-responsivity operation of quantum cascade detectors at 9 µm Open
Quantum cascade detectors (QCDs) are devices operating at zero external bias with a low dark-current. They show linear detection and high saturation intensities, making them suitable candidates for heterodyne detection in long-wave infrare…
View article: A mid-infrared lab-on-a-chip for dynamic reaction monitoring
A mid-infrared lab-on-a-chip for dynamic reaction monitoring Open
This file contains the as measured source data of the above-mentioned manuscript.
View article: A mid-infrared lab-on-a-chip for dynamic reaction monitoring
A mid-infrared lab-on-a-chip for dynamic reaction monitoring Open
This file contains the as measured source data of the above-mentioned manuscript.
View article: Shot noise in a strange metal
Shot noise in a strange metal Open
Strange-metal behavior has been observed in materials ranging from high-temperature superconductors to heavy fermion metals. In conventional metals, current is carried by quasiparticles; although it has been suggested that quasiparticles a…
View article: Silicon integrated terahertz quantum cascade ring laser frequency comb
Silicon integrated terahertz quantum cascade ring laser frequency comb Open
We demonstrate terahertz quantum cascade lasers realized in “ideal” ring resonators without discontinuities from, e.g., contacting pads. We realize this by mounting rings episide-down on a silicon substrate by a die-bonding technique. This…
View article: 2.7 <b> <i>μ</i> </b>m quantum cascade detector: Above band gap energy intersubband detection
2.7 <b> <i>μ</i> </b>m quantum cascade detector: Above band gap energy intersubband detection Open
Quantum cascade detectors (QCDs) are mid-infrared and far-infrared, low-noise, photovoltaic detectors utilizing intersubband transitions. This Letter presents an InAs/AlAs0.16Sb0.84 based QCD lattice matched to an InAs substrate. This mate…
View article: A photosensor employing data-driven binning for ultrafast image recognition
A photosensor employing data-driven binning for ultrafast image recognition Open
Pixel binning is a technique, widely used in optical image acquisition and spectroscopy, in which adjacent detector elements of an image sensor are combined into larger pixels. This reduces the amount of data to be processed as well as the…
View article: Deep learning control of THz QCLs
Deep learning control of THz QCLs Open
Artificial neural networks are capable of fitting highly non-linear and complex systems. Such complicated systems can be found everywhere in nature, including the non-linear interaction between optical modes in laser resonators. In this wo…
View article: Comb operation in terahertz quantum cascade ring lasers
Comb operation in terahertz quantum cascade ring lasers Open
Ring resonators are an interesting alternative cavity solution to the commonly used ridge-type waveguide for terahertz (THz) quantum cascade lasers. They either support a standing-wave pattern showing spatial hole burning if there are defe…
View article: High-speed quantum cascade detector characterized with a mid-infrared femtosecond oscillator
High-speed quantum cascade detector characterized with a mid-infrared femtosecond oscillator Open
Quantum cascade detectors (QCD) are photovoltaic mid-infrared detectors based on intersubband transitions. Owing to the sub-picosecond carrier transport between subbands and the absence of a bias voltage, QCDs are ideally suited for high-s…
View article: Supplementary document for Comb Operation In Terahertz Quantum Cascade Ring Lasers - 5212995.pdf
Supplementary document for Comb Operation In Terahertz Quantum Cascade Ring Lasers - 5212995.pdf Open
Simulation parameters, reference ridge data, different harmonics spectra
View article: Terahertz optical machine learning for object recognition
Terahertz optical machine learning for object recognition Open
We demonstrate an optical machine learning method in the terahertz domain, which allows the recognition of objects within a single measurement. As many materials are transparent in the terahertz spectral region, objects hidden within such …