A5000364977- Cold Atom Physics and Bose-Einstein Condensates
- Orbital Angular Momentum in Optics
- Microfluidic and Bio-sensing Technologies
- Digital Holography and Microscopy
- Quantum, superfluid, helium dynamics
- Mechanical and Optical Resonators
- Spectroscopy and Laser Applications
- Quantum optics and atomic interactions
- Strong Light-Matter Interactions
- Quantum Information and Cryptography
- Atomic and Subatomic Physics Research
- Spectroscopy Techniques in Biomedical and Chemical Research
- Electrowetting and Microfluidic Technologies
- Advanced Frequency and Time Standards
- Advanced Thermodynamics and Statistical Mechanics
- Advanced Optical Imaging Technologies
- Quantum Mechanics and Applications
- Optical Polarization and Ellipsometry
- Microfluidic and Capillary Electrophoresis Applications
- Near-Field Optical Microscopy
- Spectroscopy and Chemometric Analyses
- Advanced Fluorescence Microscopy Techniques
- Advanced X-ray Imaging Techniques
- Liquid Crystal Research Advancements
- Photonic and Optical Devices
Innsbruck Medical University
2013-2023
Universität Innsbruck
2007-2023
Centre for Biomedical Engineering and Physics
2016
University of Florence
2008-2009
Institute of Experimental Physics of the Slovak Academy of Sciences
2006
We demonstrate optical tuning of the scattering length in a Bose-Einstein condensate as predicted by Fedichev {\em et al.} [Phys. Rev. Lett. {\bf 77}, 2913 (1996)]. In our experiment atoms $^{87}$Rb are exposed to laser light which is tuned close transition frequency an excited molecular state. By controlling power and detuning beam we can change atomic over wide range. view laser-driven losses use Bragg spectroscopy fast method measure atoms.
We produce Bose-Einstein condensates of two different species, 87Rb and 41K, in an optical dipole trap proximity interspecies Feshbach resonances. discover characterize resonances, located around 35 79 G, by observing the three-body losses elastic cross section. The narrower resonance is exploited to create a double species condensate with tunable interactions. Our system opens way exploration Mott insulators and, more general, quantum phase diagram two-species Bose-Hubbard model.
Abstract Optical tweezers are tools made of light that enable contactless pushing, trapping, and manipulation objects, ranging from atoms to space sails. Since the pioneering work by Arthur Ashkin in 1970s, optical have evolved into sophisticated instruments been employed a broad range applications life sciences, physics, engineering. These include accurate force torque measurement at femtonewton level, microrheology complex fluids, single micro- nano-particle spectroscopy, single-cell...
Building on the recent experimental observation with ultracold atoms, we report first evidence of Efimov physics in a heteronuclear system. A mixture ;{41}K and ;{87}Rb atoms was cooled to few hundred nanokelvins stored an optical dipole trap. Exploiting broad interspecies Feshbach resonance, losses due three-body collisions were studied as function scattering length. We observe enhancement for three distinct values lengths, both positive negative, where no resonances are expected. attribute...
Using the technique of stimulated Raman adiabatic passage (STIRAP) we have coherently transferred ultracold (87)Rb(2) Feshbach molecules into a more deeply bound vibrational quantum level. Our measurements indicate high transfer efficiency up to 87%. Because are held in an optical lattice with not than single molecule per site, inelastic collisions between suppressed and observe long molecular lifetimes about 1 s. STIRAP created superpositions two states tested their coherence...
We have created and trapped a pure sample of 87Rb2 Feshbach molecules in three-dimensional optical lattice. Compared to previous experiments without lattice we find dramatic improvements such as long lifetimes up 700 ms near unit efficiency for converting tightly confined atom pairs into molecules. The shields the from collisions thus overcomes problem inelastic decay by vibrational quenching. Furthermore, developed novel purification scheme that removes residual atoms, resulting which...
We investigate experimentally the entropy transfer between two distinguishable atomic quantum gases at ultralow temperatures. Exploiting a species-selective trapping potential, we are able to control of one target gas in presence second auxiliary gas. With this method, drive into degenerate regime conditions controlled temperature by transferring envision that our method could be useful both achieve low entropies required realize new phases and measure atoms deep optical lattices. verified...
Spatial light modulators (SLMs) based on liquid crystals are widely used for wavefront shaping. Their large number of pixels allows one to create complex wavefronts. The crosstalk between neighboring pixels, also known as fringing field effect, however, can lead strong deviations. realized may deviate significantly from the prediction idealized assumption that response across a pixel is uniform and independent its neighbors. Detailed numerical simulations SLM full 3D physical model...
Single ions in a linear string have been addressed with tightly focused laser beam and an acousto-optic deflector. The excitation into long-lived metastable level is detected quantum jump technique. Single-quantum bit operations for information processing trapped are shown to be feasible.
We have created a dark quantum superposition state of Rb Bose-Einstein condensate and degenerate gas Rb2 ground-state molecules in specific rovibrational using two-color photo-association. As signature for the decoupling this coherent atom-molecule from light field, we observe striking suppression photo-association loss. In our experiment maximal molecule population is limited to about 100 due laser induced decay. The experimental findings can be well described by simple three mode model.
Nematic liquid crystal spatial light modulators (SLMs) with fast switching times and high diffraction efficiency are important to various applications ranging from optical beam steering adaptive optics tweezers.Here we demonstrate the great benefits that can be derived in terms of speed enhancement without loss two mutually compatible approaches.The first technique involves idea overdrive, is calculation intermediate patterns up transition target phase pattern.The second concerns...
Optical micromanipulation stands for contact-free handling of microscopic particles by light. forces can manipulate non-absorbing objects in a large range sizes, e.g., from biological cells down to cold atoms. Recently much progress has been made going the micro- down nanoscale. Less attention paid other way, trapping increasingly particles. tweezers typically employ single laser beam tightly focused microscope objective high numerical aperture stably trap particle three dimensions (3D). As...
We demonstrate a novel method of inducing an optical Feshbach resonance based on coherent free-bound stimulated Raman transition. In our experiment atoms in Rb87 Bose-Einstein condensate are exposed to two phase-locked laser beams which couple pairs colliding molecular ground state. By controlling the power and relative detuning beams, we can change atomic scattering length considerably. The dependence these parameters is studied experimentally modelled theoretically.
We report on the creation of heterospecies bosonic molecules, associated from an ultracold Bose-Bose mixture $^{41}\mathrm{K}$ and $^{87}\mathrm{Rb}$, by using a resonantly modulated magnetic field close to two Feshbach resonances. measure binding energy weakly bound molecular states versus compare our results theoretical predictions. observe broadening asymmetry association spectrum due thermal distribution atoms frequency shift occurring when depends nonlinearly field. A simple model is...
Combining several methods for contact free micro-manipulation of small particles such as cells or micro-organisms provides the advantages each method in a single setup. Optical tweezers, which employ focused laser beams, offer very precise and selective handling particles. On other hand, acoustic trapping with wavelengths about 1 mm allows simultaneous many, comparatively large With conventional approaches it is difficult to fully strengths due different experimental requirements. Here we...
A single ${}^{40}{\mathrm{Ca}}^{+}$ ion is confined in a linear Paul trap and Doppler-cooled on the ${S}_{1/2}$ to ${P}_{1/2}$ dipole transition. Then narrow quadrupole ${D}_{5/2}$ transition at 729 nm probed. The observed spectrum interpreted terms of Zeeman substructure superimposed with oscillation sidebands due harmonic motion trap. height motional provides sensitive method determine ion's temperature thus allows us test sub-Doppler laser cooling schemes needed for quantum state...
We study the horizontal transport of ultracold atoms over macroscopic distances up to 20 cm with a moving 1D optical lattice. By using an Bessel beam form lattice, we can achieve nearly homogeneous trapping conditions full length, which is crucial in order hold against gravity for such wide range. Fast velocities 6 m s−1 (corresponding about 1100 photon recoils) and accelerations 2600 s−2 are reached. Even at high momentum precisely defined uncertainty less than one recoil. This allows...
Holographic optical tweezers typically require microscope objectives with high numerical aperture and thus usually suffer from the disadvantage of a small field view working distance. We experimentally investigate an mirror trap that is created after reflection two holographically shaped collinear beams on mirror. This approach combines large distance possibility to manipulate particles in size range, since it allows use objective as low 0.2. In this work we demonstrate robust...
Direct measurement of optical forces based on recording the change momentum between in- and outgoing light does not have specific requirements particle size or shape, beam shape. Thus this approach overcomes many limitations force measurements position measurements, which require frequent calibration. In work we validate achievable accuracy for direct in axial direction a single tweezers setup, numerical simulations experimental investigations situations, where true is known. We find that...
Many applications in the life-sciences demand non-contact manipulation tools for forceful but nevertheless delicate handling of various types sample. Moreover, system should support high-resolution optical imaging. Here we present a hybrid acoustic/optical which utilizes transparent transducer, making it compatible with high-NA imaging microfluidic environment. The powerful acoustic trapping within layered resonator, is suitable highly parallel particle handling, complemented by flexibility...
Optical traps consisting of two counterpropagating, divergent beams light allow relatively high forces to be exerted along the optical axis by turning off one beam, however axial stiffness trap is generally low due lower numerical apertures typically used.Using a speed spatial modulator and CMOS camera, we demonstrate 3D servocontrol trapped particle, increasing from 0.004 1.5 µNm -1 .This achieved in "macro-tweezers" geometry [Thalhammer, J. Opt.13, 044024 (2011); Pitzek, Opt.Express 17,...