Open-path dual-comb spectroscopy measures multispecies livestock emissions, enabling future field-scale ecological studies.

The effects of state mixing by extrinsic fields in the collision region have been investigated for dielectronic recombination process ${\mathrm{Mg}}^{+}$(3s)+e\ensuremath{\rightarrow}Mg(3p,nl)\ensuremath{\rightarrow}Mg(3s ,nl)+h\ensuremath{\nu}. By field ionization Rydberg atoms produced, cross sections \ensuremath{\sigma}(${n}_{f}$) measured. observed large changes with alteration provide first incontrovertible experimental evidence that can be changed external fields.

We investigate coherent population trapping in a strongly interacting ultracold Rydberg gas. Despite the strong van der Waals interactions and interparticle correlations, we observe persistence of resonance with subnatural linewidth at single-particle frequency as tune interaction strength. This narrow cannot be understood within mean-field description Rydberg-Rydberg interactions. Instead, many-body density matrix approach, accounting for dynamics is shown to reproduce observed spectral features.

A quantum degenerate, dilute gas mixture of bosonic and fermionic atoms was produced using $^{87}\mathrm{Rb}$ $^{40}\mathrm{K}$. The onset degeneracy confirmed by observing the spatial distribution gases after time-of-flight expansion. Furthermore, magnitude interspecies scattering length between doubly spin-polarized states $^{40}\mathrm{K}$, $\ensuremath{\mid}{a}_{\mathrm{RbK}}\ensuremath{\mid}$, determined from cross-dimensional thermal relaxation. uncertainty in this collision...

Attosecond science has opened up the possibility of manipulating electrons on their fundamental timescales. Here, we use both theory and experiment to investigate ionization dynamics in helium attosecond timescale by simultaneously irradiating atom with a soft x-ray pulse train (APT) an ultrafast laser pulse. Because APT resolution energy time, observe processes that could not be observed without domains simultaneously. We show resonant absorption is important excitation small changes...

Triple photoionization of an atomic three-electron system has been observed for the first time. Triply charged lithium (``bare lithium") was found in photoion spectrum following synchrotron irradiation neutral Li vapor. Sequential decay processes, which must result at least one remaining bound electron, cannot account such triple ionization. We have measured triple-to-single ratio between 187 and 424 eV made first, rough estimate this ratio. The triple-photoionization cross section never exceeds 6 b.

Experimental details are presented for the measurement of effects extrinsic electric fields on cross sections and Rydberg product-state distributions dielectronic recombination ${\mathrm{Mg}}^{+}$ with electrons. A new type state detector is described. results in presence three field values, these compared theoretical calculations.

Charge exchange is examined with unprecedented precision using the newly developed magneto-optical trap-target recoil ion momentum spectroscopy (MOTRIMS) technique. Initial and final state selective, charge cross sections are obtained for 6 keV Cs+ colliding rubidium in 5s 5p states. For each transfer channel, differential scattering angle measured. These data used to overturn previous long-standing conjecture as origin of oscillations seen total section measurements, compare well an...

Both the coherent and incoherent pumping with intense optical radiation of electromagnetic transitions in nuclei were modeled this work. In first case anti-Stokes upconversion conventional laser was shown to be a potentially viable means for γ-ray laser. With most favorable possible arrangement nuclear energy levels, threshold stimulated output at 10 keV might reached few tens Joules isomeric media lifetimes order years. Whether such an excited states actually exists will require additional...

Utilizing two-photon excitation in hot Rb vapor we demonstrate the generation of collimated optical fields at 420 nm and 1324 nm. Input laser beams 780 776 enter a heated cell collinear circularly polarized, driving atoms to $5D_{5/2}$ state. Under phase-matching conditions coherence among $5S_{1/2}\rightarrow 5P_{3/2}\rightarrow 5D_{5/2} \rightarrow 6P_{3/2}$ transitions produces blue (420 nm) beam by four-wave mixing. We also observe forward backward propagating IR (1324 beam, due...

A modification in the analysis of a conventional laser beam spot size measurement method has been developed. The new significantly decreases uncertainty estimation beam-spot size. scanning approach was used measurement, but instead differentiating data and fitting result to Gaussian function, were fit an analytical approximation complementary error function. As result, fitted parameters obtained that consistent with standard differentiation approach, considerably smaller uncertainty.

A merged-beams electron-energy-loss technique is described, by which absolute cross sections can be measured for near-threshold electron-impact excitation of multipy charged ions. Results are reported here total the ${\mathrm{O}}^{5+}$(2s\ensuremath{\rightarrow}2p) transition from below threshold to 1.6 eV above threshold. The experimental data in good agremeent with a seven-state close-coupling calculation throughout energy range experiment. agree calculations showing that more than 90%...

In many experiments involving a magneto-optical trap (MOT) it is of great importance to know the fraction atoms placed in an excited state due trapping process. Generally speaking, researchers have had use overly simplistic and untested models estimate this fraction. work, fractions $^{87}\mathrm{Rb}$ MOT are directly measured using charge transfer technique, for range parameters. Simple then fit fractions. Using results trapped can be accurately estimated with knowledge only laser intensity...

Direct frequency comb spectroscopy is currently one of the most precise techniques for studying internal structure atomic and molecular systems. In this technique, a train ultrafast laser pulses excites states in target system which then relax, emitting fluorescence. The measured fluorescence plotted as function parameters. But according to recent theory, ultrashort from can also significantly ionize target. Here, we test theory by measuring ion signal direct spectroscopy. Furthermore,...

Direct-frequency comb spectroscopy (DFCS) is currently the highest-resolution absolute frequency spectroscopic technique known. In general, one does DFCS by scanning repetition rate, ${f}_{\mathrm{rep}}$, of a laser and measuring fluorescence from excited states species under study. The has already been successfully characterized theoretical model that starts with optical Bloch equations and, few simplifying assumptions converts them into linear coupled iterative equations. present work we...

Internal modification of silicon is important for wafer stealth dicing. In this paper, the authors report experimental and simulation results three-dimensional inside wafers using laser pulses with 1.55 μm wavelength 3.5 ns pulse duration. Permanent generated by tightly focusing continuously scanning beam samples, without damaging front back surface. Cross sections these modifications are observed after cleaving samples further analyzed mechanical polishing followed chemical etching. The...

The authors demonstrate a method for transverse writing of optical waveguides in crystalline silicon wafer using nanosecond laser with shaped beam profile that is formed by pair cylindrical lenses. In contrast to traditional methods, this avoids forming asymmetric waveguide profiles. Both straight and curved are written nearly circular guide found support single-mode propagation 1550 nm wavelength light. loss also measured.

When a train of optical pulses interacts with medium, the time between and pulse-to-pulse phase jump have profound effect on outcome interaction. For near-infinite regularly separated having constant jump, as in output frequency comb laser interacting ladder system, excitation that system has been previously calculated compared experiment. In case, number is very large, energy per pulse small. present work, other extreme experimentally examined: A small spaced are made to interact...

We report on a compact and transportable apparatus that consists of cold atomic target at the center high resolution recoil ion momentum spectrometer. Cold rubidium atoms serve as which can be operated in three different modes: continuous mode, consisting atom beam generated by two-dimensional magneto-optical trap, normal mode from are trapped three-dimensional trap (3D MOT), density 3D MOT is dark spontaneous optical configuration. The targets characterized using photoionization.

We report on a theoretical and experimental study of state-selective differential single-electron transfer cross sections between ${\mathrm{Na}}^{+}$ ions $\mathrm{Rb}(5s,5p)$ atoms at collision energies 2, 5, 7 keV. A two-center multichannel semiclassical impact parameter close-coupling method with straight-line trajectories was used to obtain capture amplitudes. By combining the eikonal approximation, we calculated angular sections. These results are compared data obtained Rb targets...

We have developed a real-time charged particle beam probe which can be used both as diagnostic (beam tuning) and to quantitatively determine the three-dimensional density distribution of beam. The consists microchannel plate, an aluminized phosphor screen deposited on fiber-optic faceplate, flexible bundle, charge injection device (CID) in tandem. Digital or analog video output CID is fed into computer oscilloscope, respectively, for analysis observation. moved continuously along beams’...

A novel apparatus has been developed in which atoms a magneto-optical trap are used as targets ion-atom collision experiments. The is an extension of earlier methodology the momentum recoiling target measured and to deduce Q value projectile scattering angle. In present work, low temperature yields increased resolution, turn leads improved angle resolution. addition, because trapping process leaves some fraction excited state, new ideal for study collisions with targets. prototypical system...

Abstract. Accurate whole-farm or herd-level measurements of livestock methane emissions are necessary for anthropogenic greenhouse gas inventories and to evaluate mitigation strategies. A controlled (CH4) release experiment was performed determine if dual comb spectroscopy (DCS) can detect CH4 concentration enhancements produced by a typical herd beef cattle in an extensive grazing system. Open-path DCS used measure downwind upwind concentrations from ten point-sources simulating emissions....