A5090262448- Perovskite Materials and Applications
- Photonic and Optical Devices
- Quantum Dots Synthesis And Properties
- Strong Light-Matter Interactions
- Photonic Crystals and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Plasmonic and Surface Plasmon Research
- Semiconductor Quantum Structures and Devices
- Quantum, superfluid, helium dynamics
- Semiconductor Lasers and Optical Devices
- Chalcogenide Semiconductor Thin Films
- Luminescence Properties of Advanced Materials
- Spectroscopy and Laser Applications
- Quantum and electron transport phenomena
- Optical Coatings and Gratings
- Mechanical and Optical Resonators
- Photorefractive and Nonlinear Optics
- Atomic and Subatomic Physics Research
- Thermal Radiation and Cooling Technologies
- Luminescence and Fluorescent Materials
- Molecular Junctions and Nanostructures
- Optical properties and cooling technologies in crystalline materials
- Neural Networks and Reservoir Computing
- Solid-state spectroscopy and crystallography
- Advanced Frequency and Time Standards
IBM Research - Zurich
2016-2025
IBM (United States)
2008-2015
Heidelberg University
2000-2011
ETH Zurich
2003-2006
Darmstadt University of Applied Sciences
1976
We study 1D trapped Bose gases in the strongly interacting regime. The systems are created an optical lattice and subject to a longitudinal periodic potential. Bragg spectroscopy enables us investigate excitation spectrum different regimes. In superfluid phase broad continuum of excitations is observed which calls for interpretation beyond Bogoliubov taking into account effect strong interactions. Mott insulating discrete measured. Both phases compared 3D situation crossover regime from 3D....
We have studied interacting and noninteracting quantum degenerate Fermi gases in a three-dimensional optical lattice. directly image the surface of atoms lattice by turning off adiabatically. Because confining potential, gradual filling transforms system from normal state into band insulator. The dynamics transition insulator to is studied, time scale measured be an order magnitude larger than tunneling Using Feshbach resonance, we increase interaction between two different spin states...
We report on the realization of a trapped one-dimensional Bose gas and its characterization by means measuring lowest lying collective excitations. The quantum degenerate is prepared in 2D optical lattice, we find ratio frequencies compressional (breathing) mode dipole to be (omega(B)/omega(D))(2) approximately 3.1, accordance with Lieb-Liniger mean-field theory. For thermal measure 4. By heating gas, have studied transition between two regimes. number particles attainable experiment kinetic...
We have observed two-particle bound states of atoms confined in a one-dimensional matter waveguide. These exist irrespective the sign scattering length, contrary to situation free space. Using radio-frequency spectroscopy we measured binding energy these dimers as function length and confinement find good agreement with theory. The strongly interacting Fermi gas which create an optical lattice represents realization tunable Luttinger liquid.
Metal-halide semiconductors with perovskite crystal structure are attractive due to their facile solution processability, and have recently been harnessed very successfully for high-efficiency photovoltaics bright light sources. Here, we show that at low temperature single colloidal cesium lead halide (CsPbX3, where X = Cl/Br) nanocrystals exhibit stable, narrow-band emission suppressed blinking small spectral diffusion. Photon antibunching demonstrates unambiguously nonclassical...
Abstract The brightness of an emitter is ultimately described by Fermi’s golden rule, with a radiative rate proportional to its oscillator strength times the local density photonic states. As intrinsic material property, quest for ever brighter emission has relied on states engineering, using dielectric or plasmonic resonators 1,2 . By contrast, much less explored avenue boost strength, and hence rate, collective behaviour termed superradiance. Recently, it was proposed 3 that latter can be...
We have studied mixtures of fermionic (40)K and bosonic (87)Rb quantum gases in a three-dimensional optical lattice. observe that an increasing admixture the species diminishes phase coherence atoms as measured by studying both visibility matter wave interference pattern length bosons. Moreover, we find attractive interactions between bosons fermions lead to increase boson density lattice which measure three-body recombination In our data, do not loss atoms. An analysis thermodynamics...
We create molecules from fermionic atoms in a three-dimensional optical lattice using Feshbach resonance. In the limit of low tunneling, individual wells can be regarded as independent harmonic oscillators. The measured binding energies for varying scattering length agree excellently with theoretical prediction two interacting oscillator. demonstrate that formation used to measure occupancy and perform thermometry.
The lowest stationary quantum state of neutrons in the Earth's gravitational field is identified measurement neutron transmission between a horizontal mirror on bottom and an absorber top. Such assembly not transparent for if height smaller than "height" state.
We study a spin-polarized degenerate Fermi gas interacting via $p$-wave Feshbach resonance in an optical lattice. The strong confinement available this system allows us to realize one- and two-dimensional gases and, therefore, restrict the asymptotic scattering states of atomic collisions. When aligning spins along (or perpendicular to) axis motion one-dimensional gas, into channels with projection angular momentum $|m|=1$ $m=0$) can be inhibited. In two three dimensions, we observe doublet...
Colloidal semiconductor quantum structures allow controlling the strong confinement of charge carriers through material composition and geometry. Besides being a unique platform to study fundamental effects, these materials attracted considerable interest due their potential in opto-electronic communication applications. Heteronanostructures like CdSe/CdS offer new prospects tailor optical properties as they take advantage small conduction band offset allowing tunability electron...
Ultrafast and highly efficient optical modulators that are based on the Pockels effect key components of today's communication networks. For next generation photonic links, silicon technology is used to establish a new wave densely integrated optic components. However, this cannot exploit advantages using for switching two reasons: First, does not exhibit any effect, second, attempts combine nonlinear materials with photonics have been cumbersome. Here, we demonstrate path integrate barium...
Ligand-capped nanocrystals (NCs) of lead halide perovskites, foremost fully inorganic CsPbX3 NCs, are the latest generation colloidal semiconductor quantum dots. They offer a set compelling characteristics—large absorption cross section, as well narrow, fast, and efficient photoluminescence with long exciton coherence times—rendering them attractive for applications in light-emitting devices optics. Monodisperse shape-uniform, broadly size-tunable, scalable, robust NC samples paramount...
Hybrid SiN-QD microlasers coupled to a passive SiN output waveguide with 7{\mu}m diameter and record low threshold density of 27 {\mu}J cm-2 are demonstrated. A new design unique processing scheme starting from SiN/QD/SiN stacks offer long term stability facilitate in depth laser characterization. This approach opens up paths for optical communication, lab-on-a-chip, gas sensing and, potentially, on-chip cavity quantum electrodynamics optics.
Nanocrystal superlattices (NC SLs) have long been sought as promising metamaterials, with nanoscale-engineered properties arising from collective and synergistic effects among the constituent building blocks. Lead halide perovskite (LHP) NCs come across outstanding candidates for SL design, they demonstrate light emission, known superfluorescence, in single- multicomponent SLs. Thus far, LHP only assembled single-component SLs or coassembled dielectric NC blocks acting solely spacers between...
We prepare a Bose-Einstein condensed gas in three-dimensional optical lattice and study the excitation spectrum of superfluid phase for different interaction strengths. probe response system by modulating depth along one axis. The interactions can be controlled independently varying tunnel coupling other two axes. In weakly interacting regime we observe small susceptibility to excitations, while stronger an unexpected resonance appears spectrum. addition measure coherent fraction atomic gas,...
We describe the design, fabrication, and characterization of a 1-dimensional silicon photonic crystal cavity with quality factor-to-mode volume ratio greater than 10(7), which exceeds highest previous values by an order magnitude. The maximum electric field is outside in void formed central slot. An extremely small calculated mode 0.0096 (λvac/n)(3) achieved through abrupt change slot, despite high factor 8.2 × 10(5) predicted simulation. Quality factors up to 1.4 are measured actual...