We have created a long-lived ($\ensuremath{\approx}40\text{ }\text{ }\mathrm{s}$) persistent current in toroidal Bose-Einstein condensate held an all-optical trap. A repulsive optical barrier across one side of the torus creates tunable weak link circuit, which can affect around loop. Superflow stops abruptly at strength such that local flow velocity exceeds critical velocity. The measured is consistent with dissipation due to creation vortex-antivortex pairs. This system first realization...

We present experimental results on a Bose gas in quasi-2D geometry near the Berezinskii, Kosterlitz and Thouless (BKT) transition temperature. By measuring density profile, \textit{in situ} after time of flight, coherence length, we identify different states gas. In particular, observe that develops bimodal distribution without long range order. this state, presents longer length than thermal cloud; it is quasi-condensed but not superfluid. Experimental evidence indicates superfluid (BKT transition).

We have previously demonstrated a pulsed direct detection IPDA lidar to measure range and the column concentration of atmospheric CO2. The measures backscatter profiles samples shape 1,572.33 nm CO2 absorption line. participated in ASCENDS science flights on NASA DC-8 aircraft during August 2011 report here measurements made four over variety surface cloud conditions near US. These included stratus deck Pacific Ocean, dry lake bed surrounded by mountains Nevada, desert area with coal-fired...

Abstract. Here we report on measurements made with an improved CO2 Sounder lidar during the ASCENDS 2014 and 2016 airborne campaigns. The changes to 2011 version of included incorporating a rapidly wavelength-tunable, step-locked seed laser in transmitter, using much more sensitive HgCdTe APD detector analog digitizer faster readout time receiver. We also lidar's calibration approach XCO2 retrieval algorithm. flights were over several types topographic surfaces from 3 12 km aircraft...

We report airborne measurements of the column abundance atmospheric methane made over an altitude range 3-11 km using a direct detection integrated-path differential-absorption lidar with pulsed laser emitting at 1651 nm. The transmitter was tunable, seeded optical parametric amplifier pumped by Nd:YAG laser, and receiver used photomultiplier detector photon-counting electronics. results follow expected changes aircraft altitude, measured line shapes depths show good agreement theoretical...

Abstract. We have measured the column-averaged atmospheric CO2 mixing ratio to a variety of cloud tops by using an airborne pulsed multi-wavelength integrated-path differential absorption (IPDA) lidar. Airborne measurements were made at altitudes up 13 km during 2011, 2013 and 2014 NASA Active Sensing Emissions over Nights, Days, Seasons (ASCENDS) science campaigns flown in United States West Midwest compared those from situ sensor. Analysis lidar backscatter profiles shows average top...

Abstract We have measured the CO 2 volume mixing ratio (VMR) within planetary boundary layer (PBL) using cloud slicing with an airborne pulsed integrated path differential absorption (IPDA) lidar from flight altitudes of up to 13 km. During a over Iowa in summer 2011, simultaneous measurement optical range and clouds ground were made time‐resolved detection pulse echoes each scattering surface. determined PBL by differencing two lidar‐measured line shapes, one broken shallow cumulus located...

We present column CO2 measurements taken by the passive miniaturized laser heterodyne radiometer (Mini-LHR) at 1611.51 nm Mauna Loa Observatory in Hawaii. The Mini-LHR was operated autonomously, during month of May 2013 this site, working tandem with an AERONET sun photometer that measures aerosol optical depth 15-min intervals daylight hours. Laser radiometry has been used since 1970s to measure atmospheric gases such as ozone, water vapor, methane, ammonia, chlorine monoxide, and nitrous...

Partial-transfer absorption imaging is a tool that enables optimal of atomic clouds for wide range optical depths. In contrast to standard imaging, the technique can be minimally destructive and used obtain multiple successive images same sample. The involves transferring small fraction sample from an initial internal state auxiliary subsequently absorptively on cycling transition. atoms remaining in are essentially unaffected. We demonstrate technique, discuss its applicability, compare...

We present a design for 4 U (20 cm × 20 10 cm) occultation-viewing laser heterodyne radiometer (LHR) that measures methane (CH4), carbon dioxide (CO2) and water vapor (H2O) in the limb is designed deployment on 6 CubeSat. The LHR collects sunlight has undergone absorption by trace gas mixes it with distributive feedback (DFB) centered at 1640 nm scans across CO2, CH4, H2O features. Upper troposphere/lower stratosphere measurements of these gases provide key inputs to stratospheric...

Abstract. The retrieval algorithm for CO2 column mixing ratio from measurements of a pulsed multi-wavelength integrated path differential absorption (IPDA) lidar is described. samples the shape 1572.33 nm line at multiple wavelengths. uses least-squares fit between computed layered atmosphere model and that sampled by lidar. In addition to column-average dry-air mole fraction (XCO2), several other parameters are also solved simultaneously fit. These include Doppler shift received laser...

We study the phase-fluctuating condensate regime of ultracold atoms trapped in a ring-shaped trap geometry, which has been realized recent experiments. first consider simplified box we identify conditions to create state that is dominated by thermal phase fluctuations, and then explore experimental ring geometry. In both cases demonstrate requirement for strong fluctuations can be expressed terms total number geometric length scales only. For discuss zero temperature limit where fluctuating...

We used an airborne pulsed integrated path differential absorption lidar to make spectroscopic measurements of the pressure-induced line broadening and center shift atmospheric carbon dioxide at 1572.335 nm line. scanned wavelength over 13 GHz (110 pm) measured lineshape 30 discrete wavelengths in vertical column between aircraft ground. A comparison our calculations based on HIgh-resolution TRANsmission molecular database shows excellent agreement with peak optical depth accurate within...

We have observed the persistent flow of Bose-condensed atoms in a toroidal trap. The persists without decay for up to 10 s, and was initiated by transferring one unit, ħ, orbital angular momentum from Laguerre-Gaussian photons each atom. Stable only possible when trap multiply-connected, with BEC fraction as small 15%. also created two units momentum, its splitting into singly-charged vortices geometry changed multiply- simply-connected.

Abstract. We review the singular value decomposition (SVD) framework and use it for quantifying discerning vertical information in greenhouse gas retrievals from column integrated absorption measurements. While commonly used traditional Bayesian optimal estimation (OE) assumes a prior distribution order to regularize inversion problem, SVD approach identifies principal components that can be retrieved measurement without explicitly specifying mean covariance matrix. method, recognize of an...

We describe the coherent transfer of orbital angular momentum a photon to an atom in quantized units ℏ, using 2-photon stimulated Raman process with Laguerre-Gaussian beams generate atomic vortex state Bose-Einstein condensate (BEC) sodium atoms. show that is by creating superpositions different states, where relative phase between states determined phases optical fields. use this technique circular flow BEC confined toriodal shaped trap. measure atoms persists for up 10 seconds, which we...

Abstract. Here we report on measurements made with an improved CO2 Sounder lidar during the ASCENDS 2014 and 2016 airborne campaigns. The improvements to 2011 version of instrument included incorporating a rapidly wavelength tunable, step-locked seed laser in transmitter, using much more sensitive HgCdTe APD detector, analog digitizer faster readout time receiver. We also lidar’s calibration approach XCO2 retrieval algorithm. flights were over several types topographic surfaces from 3–12 km...

Trace gases and their isotopic ratios in planetary atmospheres offer important but subtle clues as to the origins of a planet's atmosphere, hydrology, geology, potential for biology. An orbiting laser remote sensing instrument capable measuring trace on global scales with unprecedented accuracy high spatial resolution can provide valuable measurements earth science missions.

A high efficiency, narrow linewidth tunable laser source is developed for greenhouse trace gas remote sensing. It features broad, continuous tuning range at 1570-1655 nm and 3291 with (500 MHz) spectral purity. This based on seeded optical parametric generator (OPG) technology. Several species were continuously detected 72 hours in an open path environment. We also present our recent airborne experiment result this

We have advanced the science of space-based laser measurements using spectral purity and frequency tuning a fiber-amplified lasers performing active remote sensing atmospheric CO2 column abundance dry mixing ratio.

We demonstrate the airborne measurement of atmospheric methane using a pulsed lidar at 1650 nm an integrated path differential absorption scheme. Our seeded nanosecond-pulsed optical parametric amplifier (OPA)-based instrument works up to highest altitudes flown (<10 km). The obtained profile is in good agreement with theoretical predictions based on HITRAN database.

Abstract. We have measured the column-averaged atmospheric CO2 mixing ratio to a variety of cloud tops by using an airborne pulsed multiple wavelengths integrated-path, differential absorption (IPDA) lidar. Airborne measurements were made at altitudes up 13 km during 2011, 2013 and 2014 ASCENDS science campaigns flown in west mid-west United States compared those from situ sensor. Analysis lidar backscatter profiles show average top reflectance was ~ 5 % for measurement 1572.335 nm except...