A5088692078- Spectroscopy and Laser Applications
- Photonic and Optical Devices
- Semiconductor Lasers and Optical Devices
- Semiconductor Quantum Structures and Devices
- Terahertz technology and applications
- Laser Design and Applications
- Advanced Fiber Laser Technologies
- Atmospheric Ozone and Climate
- Laser-induced spectroscopy and plasma
- Laser-Plasma Interactions and Diagnostics
- Gas Sensing Nanomaterials and Sensors
- Spectroscopy and Quantum Chemical Studies
- Quality and Safety in Healthcare
- Neural Networks and Reservoir Computing
- Spectroscopy Techniques in Biomedical and Chemical Research
- Atmospheric and Environmental Gas Dynamics
- Optical Systems and Laser Technology
- Laser Material Processing Techniques
- Atomic and Molecular Physics
- Magnetic confinement fusion research
- Laser-Matter Interactions and Applications
- Strong Light-Matter Interactions
- Optical Wireless Communication Technologies
- Optimal Experimental Design Methods
- Particle Detector Development and Performance
ETH Zurich
2018-2025
IBM Research - Zurich
2017-2022
University of Glasgow
2019-2021
University of Pisa
2021
Roma Tre University
2021
Los Alamos National Laboratory
2017
We present homogeneous quantum cascade lasers (QCLs) emitting around 3 THz which display bandwidths up to 950 GHz with a single stable beatnote. Devices are spontaneously operating in harmonic comb state, and when dense mode regime, they can be injection locked at the cavity roundtrip frequency very small RF powers down −55 dBm. When operated electrically unstable region of negative differential resistance, device displays ultrabroadband operation exceeding 1.83 (Δf/f = 50%) high phase...
We miniaturize a vertically coupled in-plane whispering gallery mode cavity incorporating quantum cascade gain medium, aiming to realize the mid-infrared counterpart vertical surface emitting laser. Building on previous work with linear microcavities, we introduce new type of laser (QCSEL) by miniaturizing buried heterostructure ring cavity. At wavelengths 4.5 and 8 μm, investigate optical losses for decreasing diameters while benchmarking device performance against microcavities. achieve an...
Abstract A low‐cost single frequency laser, emitting in the mid‐infrared spectral region and dissipating minimal electrical power, is a key ingredient for next generation of portable gas sensors high‐volume applications involving chemical sensing important greenhouse pollutant gases. Herein, Quantum Cascade Surface Emitting Laser (QCSEL) proposed, which implemented as short linear cavity with high reflectivity coated end‐mirrors to suppress any edge emission employs buried semiconductor...
n-type Ge/SiGe terahertz quantum cascade lasers are investigated using non-equilibrium Green's functions calculations. We compare the temperature dependence of gain properties with an equivalent GaAs/AlGaAs laser design. In case, is found to be much more robust increase, enabling operation up room temperature. The better robustness respect III–V attributed weaker interaction optical phonons. effect lower interface quality and can partly overcome by engineering smoother confinement.
The ZnO-based heterostructures are predicted to be promising candidates for optoelectronic devices in the infrared and terahertz (THz) spectral domains owing their intrinsic material properties. Specifically, large ZnO LO-phonon energy reduces thermally activated scattering, which is greatly improve temperature performance of THz quantum cascade lasers. However, date, no experimental observation intersubband emission from has been reported. Here, we report electroluminescence ZnO/MgxZn1–xO...
We report electroluminescence originating from L-valley transitions in n-type Ge/Si$_{0.15}$Ge$_{0.85}$ quantum cascade structures centered at 3.4 and 4.9 THz with a line broadening of $\Delta f/f \approx 0.2$. Three strain-compensated heterostructures, grown on Si substrate by ultrahigh vacuum chemical vapor deposition, have been investigated. The design is based single well active region employing vertical optical transition the observed spectral features are described non-equilibrium...
A new metal forming lubricant based on polymeric materials has been developed. The developed through emulsion copolymerization. Copolymers with the common composition of stearyl methacrylate and 2-hydroxyethyl acid phosphate were made three secondary polymers: methyl methacrylate, butyl acrylate, methacrylate. performance was evaluated using ring compression twist tests. compared against a zinc-phosphate-coating-based lubricant, commonly used in forging, other commercial lubricants....
Abstract Understanding and controlling the nonlinear optical properties coherent quantum evolution of complex multilevel systems out equilibrium is essential for new semiconductor device generation. In this work, we investigate system an unbiased cascade structure by performing two-dimensional THz spectroscopy. We study time-resolved after it driven far from strong pulses demonstrate existence multiple signals originating engineered subbands find lifetimes those states to be in order 4–8 ps....
THz quantum cascade lasers (QCLs) based on double metal waveguides feature broadband and high-temperature devices for their use in spectroscopy sensing. However, extreme field confinement produces poor output coupling efficiencies divergent far-fields. Here, we present a planarized QCL with an inverse-designed end facet reflector coupled to surface-emitting patch array antenna. All the components have been optimized octave-spanning spectral bandwidths between 2 4 monolithically integrated...
We demonstrate multi-level optical weights embedded in a silicon photonic platform based on ferroelectric domain switching. Ferroelectric barium titanate integrated resonator structures is used as the memory material. By applying short voltage pulses of 100ns, we can switch fractions domains and thus change transmission waveguides by more than one order magnitude non-volatile way. achieve 10 distinct levels, show iterative switching synaptic element polarity, magnitude, number applied...
Predictive maintenance (PdM) is cited by the ITRS as a critical technology to incorporate into production over next five years reduce unscheduled downtime and cycle time, maintain high quality, cost. Equipment Health monitoring (EHM) companion PdM that provides tracking indication of equipment health. The industry needs deploy assess EHM capabilities determine best practices for potential cost reduction through deployment these technologies. Applied Materials working with both Micron...
High-quality n-type continuously graded Ge-rich Si1−xGex parabolic quantum wells with different doping levels were grown by using ultrahigh-vacuum chemical vapor deposition on Si(001) substrates. A thorough structural characterization study highlights an ideal compositional profile. THz intersubband absorption has been investigated in modulation-doped samples and directly doped the wells. The comparison of experimental data theoretical calculations allowed us to quantify impact electron...
Quantum-cascade-laser (QCL) frequency combs are compact semiconductor light sources operating in the mid-IR and terahertz frequencies. Achieving subpicosecond laser pulses with high peak power is of vital importance for performing nonlinear time-resolved spectroscopy as well exploring phenomena. Therefore, investigation characterization free-running emission a key further improvement optimization these intersubband devices. In this work, we demonstrate direct electric field measurement QCL...
This paper outlines the major challenges for development of 193 nm immersion and extreme ultraviolet (EUV) resists. The issues implementation are developing high index fluids lens materials to enable 32 half-pitch imaging. For EUV resists, reaction mechanisms not well understood. In addition, many constraints placed on such as needing low photospeed, line width roughness, outgassing while achieving desired resolution, make resist design very difficult.
A crucial element for the next generation of portable gas sensors high-volume applications, especially involving chemical sensing important greenhouse and pollutant gases, is development a low-cost, low-power consuming, single-frequency laser operating in mid-infrared spectral range. In this regard, we propose implementation Quantum Cascade Surface Emitting Laser (QCSEL). Our design involves linear microcavity with high reflectivity coated end-mirrors buried semiconductor diffraction grating...
We miniaturize a vertically-coupled in-plane whispering gallery mode cavity incorporating quantum cascade gain medium, aiming to realize the mid-infrared counterpart vertical surface emitting laser (VCSEL). Building on previous work with linear microcavities, we introduce new type of (QCSEL) by miniaturizing buried heterostructure ring cavity. At wavelengths 4.5 ${\mu}$m and 8 ${\mu}$m, investigate optical losses for decreasing diameters while benchmarking device performance against...
Terahertz (THz) semiconductor based quantum cascade lasers (QCLs) represent powerful and compact integrated light sources. To date they have been realized with various III-V materials where LO phonon emission becomes very effective as the temperature is increased, limiting maximum operating to 200K. overcome this limitation, non-polar material systems are attractive because of their weaker e-phonon interaction. Theoretical studies indicated n-type Ge/SiGe heterostructures transport...
Hermetic packaging of micro-optoelectromechanical systems (MOEMS) is an immature technology, lacking industry-consensus methods and standards. Off-the-shelf, catalog window assemblies are not yet available. Window in general custom designed manufactured for each new product, resulting longer than acceptable cycle times, high procurement costs questionable reliability. There currently two dominant window-manufacturing wherein a metal frame attached to glass, as well third, less-used method....
We present homogeneous quantum cascade lasers (QCLs) emitting around 3 THz which display bandwidths up to 950 GHz with a single stable beatnote. Devices are spontaneously operating in harmonic comb state, and when dense mode regime they can be injection locked at the cavity roundtrip frequency very small RF powers down -55 dBm. When operated electrically unstable region of negative differential resistance, device displays ultra-broadband operation exceeding 1.83 ($Δf/f=50\%$) high phase...
Augmented and mixed reality applications have recently gained large interest. In order to fabricate lightweight near eye displays surface relief gratings are used for coupling the light from source into guide out of towards eye. To suppress higher diffraction orders thus maximize yield those slanted. achieve high field view variation slant angle is desirable yet rather difficult achieve. Ion beam trimming (IBT) a method well established in MEMS sensor manufacturing locally modify thickness...