We report on the observation of a highly degenerate, strongly interacting Fermi gas atoms. Fermionic lithium-6 atoms in an optical trap are evaporatively cooled to degeneracy using magnetic field induce strong, resonant interactions. Upon abruptly releasing cloud from trap, is observed expand rapidly transverse direction while remaining nearly stationary axial direction. interpret expansion dynamics terms collisionless superfluid and collisional hydrodynamics. For data taken at longest...

We observe collective oscillations of a trapped, degenerate Fermi gas $^6$Li atoms at magnetic field just above Feshbach resonance, where the two-body physics does not support bound state. The exhibits radial breathing mode frequency 2837(05) Hz, in excellent agreement with $\nu_H\equiv\sqrt{10\nu_x\nu_y/3}=2830(20)$ Hz predicted for {\em hydrodynamic} unitarity limited interactions. measured damping times and frequencies are inconsistent predictions both collisionless mean regime...

This paper describes a single-shot spectral imaging approach based on the concept of compressive sensing. The primary features system design are two dispersive elements, arranged in opposition and surrounding binary-valued aperture code. In contrast to thin-film approaches filtering, this structure results easily-controllable, spatially-varying, filter functions with narrow features. Measurement input scene through these filters is equivalent projective measurement domain, hence can be...

Dielectric reflectarray antennas are proposed as a promising low-loss and low-cost solution for high gain terahertz (THz) antennas. Variable height dielectric elements used in the designs, which allow use of low dielectric-constant materials. Polymer-jetting 3-D printing technology is utilized to fabricate antenna, makes it possible achieve rapid prototyping at low-cost. Numerical experimental results presented 3 different prototypes operating 100 GHz, show good performance. Moreover...

In this work, we designed, built, and tested a low-gain 20 dBi Luneburg Lens antenna using rapid prototyping machine as proof of concept demonstrator. The required continuously varying relative permittivity profile was implemented by changing the size plastic blocks centered on junctions rod space frame. A 12-cm ( 4λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> at 10 GHz) diameter lens is designed to work X-band. effective unit cell...

We achieve degeneracy in a mixture of the two lowest hyperfine states 6Li by direct evaporation CO2 laser trap, yielding first all optically produced degenerate Fermi gas. More than 10(5) atoms are confined at temperatures below 4 microK full trap depth, where temperature for each state is 8 microK. This two-component ideal exploring mechanisms superconductivity ranging from Cooper pairing to Bose-Einstein condensation strongly bound pairs.

A Fokker-Planck equation is derived for the energy distribution of atoms in a three-dimensional harmonic trap with fluctuations spring constant and equilibrium position. Using this model, we predict lifetimes based on measurable noise spectra fluctuations. The distributions evolve into single eigenmode where apparent temperature remains while population decays as consequence input. method analysis corresponding results are applicable to any optical, magnetic, or ion that approximately...

A strongly attractive, two-component Fermi gas of atoms exhibits universal behavior and should be mechanically stable as a consequence the quantum-mechanical requirement unitarity. This limits maximum attractive force to value smaller than that outward pressure. To experimentally demonstrate this stability, we use all-optical methods produce highly degenerate, ${}^{6}\mathrm{Li}$ in an applied magnetic field near Feshbach resonance, where strong interactions are observed. We find is at...

An all-dielectric THz waveguide has been designed, fabricated and characterized. The design is based on a hollow-core electromagnetic crystal waveguide, the fabrication implemented via polymer-jetting rapid prototyping. Measurements of power loss factor show good agreement with simulation. As an initial example, propagation 0.03 dB/mm at 105 GHz demonstrated.

We investigate the utility of compressive sensing (CS) to electro-optic and infrared (EO/IR) applications. introduce field through a discussion historical antecedents development modern CS framework. Basic economic arguments (in broadest sense) are presented regarding applicability EO/IR used draw conclusions application areas where would be most viable. A number experimental success stories demonstrate overall feasibility approaches, we conclude with open challenges practical adoption methods.

The inpainting of deliberately and randomly sub-sampled images offers a potential means to image specimens at high resolution under extremely low-dose conditions (≤1 e−/Å2) using scanning transmission electron microscope. We show that deliberate sub-sampling acquires least an order magnitude faster than conventional methods for equivalent dose. More importantly, when adaptive is implemented acquire the images, there significant increase in sensitivity which accompanies imaging speed....

Performing imaging with scattered light is challenging due to the complex and random modulation imposed upon by scatterer. Persistent correlations, such as optical memory effect (ME), enable high-fidelity, diffraction-limited through scattering media without any prior knowledge of or access media. However, conventional ME techniques have been limited gray-scale imaging. We overcome this restriction using spectral coding compressed sensing realize snapshot color demonstrate our method obtain...

We derive scaling laws for the number of atoms, collision rate, and phase-space density as a function trap depth evaporative cooling in an adiabadically lowered optical trap. The results are excellent agreement with Boltzmann equation model show that very large increases can be obtained without excessive slowing evaporation rate. Predictions reasonable recent experiment achieves Bose-Einstein condensation by also discuss fermionic mixtures explain why Pauli blocking does not strongly inhibit cooling.

We measure a zero crossing in the scattering length of mixture two lowest hyperfine states 6-Li. To locate crossing, we monitor decrease temperature and atom number arising from evaporation CO2 laser trap as function magnetic field B. The loss are minimized for B=528(4) G, consistent with no evaporation. also present preliminary calculations using potentials that have been constrained by measured broad Feshbach resonance at approximately 860 agreement previous theoretical predictions. In...

We demonstrate an ultrastable ${\mathrm{CO}}_{2}$ laser trap that provides tight confinement of neutral atoms with negligible optical scattering and minimal laser-noise-induced heating. Using this method, fermionic ${}^{6}\mathrm{Li}$ are stored in a 0.4 mK deep well $1/e$ lifetime 300 sec, consistent background pressure ${10}^{\ensuremath{-}11}\mathrm{Torr}$. To our knowledge, is the longest storage time ever achieved all-optical trap, comparable to best reported magnetic traps.

We propose a new class of aperture-coded spectrometer that is optimized for the spectral characterization diffuse sources. The instrument achieves high throughput and resolution by replacing slit conventional dispersive spectrometers with more complicated spatial filter. develop general mathematical framework deriving required aperture codes discuss several appealing code families. Experimental results validate performance instrument.

An all-dielectric terahertz (THz) horn antenna based on hollow-core electromagnetic crystal structure is designed, fabricated and characterized. Simulation shows that the works above 100 GHz, with better than 30 dB return loss highly directional radiation pattern. Fabrication of done using a THz polymer-jetting rapid prototyping technique. Characterization performed time-domain spectrometer. Measurement results far-field patterns show good agreement simulation results.

Modern rapid prototyping technologies are now capable of build resolutions that allow direct fabrication photonic structures in the GHz and THz frequency regimes. To demonstrate this, we have fabricated several with 3D electromagnetic bandgaps 100-400 range. Characterization these via Time-domain Spectroscopy (THz-TDS) shows very good agreement simulation, confirming accuracy approach. This inexpensive 3-D method may be useful for a variety potential applications.

We derive a simple formula for the heating rate that arises from quantum-diffractive background gas collisions in atom traps. This result appears to explain residual rates reported recent experiments with Cs vapor-loaded, far-detuned optical trap at $\ensuremath{\simeq}{10}^{\ensuremath{-}9}$ Torr [Phys. Rev. Lett. 81, 5768 (1998)]. Diffractive may determine minimum achievable shallow all-optical or magnetic traps operating low temperature and high density.

Terahertz digital off-axis holography (THzDH) has been demonstrated as a non-destructive tool for imaging voids within visually opaque dielectrics. Using raster scanning heterodyne detector, the imager captures lensless transmission holograms formed by interaction of highly coherent, monochromatic beam with 3-D printed structures. Digital hologram reconstructions from two structures were used to measure imager's modulation transfer function and show that terahertz can provide sub-millimeter...

Anthropomorphic breast phantoms mimic patient anatomy in order to evaluate clinical mammography and digital tomosynthesis system performance. Our goal is create a modular phantom with an anthropomorphic region allow for improved lesion calcification detection as well uniform standard quality control (QC) metrics. Previous versions of this used commercial photopolymer inkjet three-dimensional printers recreate using four surfaces that were fabricated materials spanning only limited density...

Coded aperture spectroscopy allows for sources of large étendue to be efficiently coupled into dispersive spectrometers by replacing the traditional input slit with a patterned mask. We describe coded spectrometer optimized Raman diffuse sources, (e.g., tissue). provide design details system, along quantitative estimation results ethanol at non-toxic levels in lipid tissue phantom. With 60 mW excitation power 808 nm, leave-one-out and blind cross-validation partial least squares (PLS)...

A spectral imager provides a 3-D data cube in which the spatial information (2-D) of image is complemented by (1-D) about each location. Typically, these systems are operated fully-determined (or overdetermined) manner so that measurements can be computationally inverted into reliable estimate source. We propose notional system design highly underdetermined, yet still invertable. This approach relies on recently-developed concepts compressive sensing. Because number required greatly reduced...

We use an all-optical trap to confine a strongly attractive two-state mixture of lithium fermions. By measuring the rate evaporation from trap, we determine effective elastic scattering cross section 4pia(2) show that magnitude length |a| is very large, in agreement with predictions. stable against inelastic decay provided small bias magnetic field applied. For this system, s-wave interaction widely tunable at low field, and can be turned on off rapidly via Raman pi pulse. Hence, well suited...