Optical dipole traps and fractional Talbot optical lattices based on the interference between multiple co-propagating laser beams are proposed. The variation of relative amplitudes and phases of the interfering light beams of these traps makes it possible to manipulate the spatial position of trapped atoms. Examples of spatial translation and splitting of atoms between a set of the interference traps are considered. The prospect of constructing all-light atom chips based on the proposed technique is presented.
We present a method to obtain power-balanced laser beams for doing quantum-state manipulation experiments with phase-stable double optical lattices. Double optical lattices are constructed using four pairs of overlapped laser beams with different frequency. Our optical scheme provides a phase stability between the optical lattices of 5 mrad/s and laser beams with a very clean polarisation state resulting in a power imbalance in the individual laser beams of less than 1%.
Nondipole effects are ubiquitous and crucial in light-matter interaction. However, they are too weak to be directly observed. In strong-field physics, motion of electrons is mainly confined in transverse plane of light fields, which suppresses the significance of nondipole effects. Here, we present a theoretical study on enhancing and controlling the nondipole effect by using the synthesized two perpendicularly propagating laser fields. We calculate the three-dimensional photoelectron momentum distributions of strong-field tunneling ionization of hydrogen atoms using the classical trajectory M…
We observed two-photon emission signals from the first vibrationally excited state of parahydrogen gas excited coherently by counter-propagating laser pulses. A single narrow-linewidth laser source was used to excite the parahydrogen molecules and induce the two-photon emission process. We measured how the signal energy depended on the detuning, target gas pressure, and input pulse energies. These results are qualitatively consistent with those obtained by numerical simulations based on the Maxwell-Bloch equations with one spatial dimension and one temporal dimension. This study of two-photon …
In this work we study propagation dynamics of the two counter-propagating lasers, the continuous-wave (CW) laser and the pulse of another laser, when both lasers are tuned to the $F_{g}=2 \rightarrow F_{e}=1$ transition in $^{87}$Rb, and therefore can develop Hanle electromagnetically induced transparency (EIT) in Rb vapor. We calculate transmission of both lasers as a function of applied magnetic field, and investigate how the propagation of the pulse affects the transmission of the CW laser. And vice versa, we have found conditions when the Gaussian pulse can either pass unchanged, or be sig…
We describe optimized coherent control methods for two-photon transitions in atoms of a ladder-type three-state energy configuration. Our approach is based on the spatial coherent control scheme which utilizes counter-propagating ultrashort laser pulses to produce complex excitation patterns in an extended space. Since coherent control requires constructive interference of constituent transition pathways, applying it to an atomic transition with a specific energy configuration requires specially designed laser pulses. Here, we show, in an experimental demonstration, that the two-photon transit…
We present and investigate different external cavity diode laser (ECDL) configurations for the manipulation of neutrals atoms, wavelength-stabilized by a narrow-band high transmission interference filter. A novel diode laser, providing high output power of more than 1 W, with a linewidth of less than 200 kHz, based on a self-seeded tapered amplifier chip has been developed. Additionally, we compare the optical and spectral properties of two laser systems based on common laser diodes, differing in their coating, as well as one, based on a distributed-feedback (DFB) diode. The linear cavity setu…
We present an innovative fiber laser system for both cesium and rubidium manipulation. The architecture is based on frequency conversion of two lasers at 1560 nm and 1878 nm. By taking advantage of existing fiber components at these wavelengths, we demonstrate an all fiber laser system delivering 350 mW at 780 nm for rubidium and 210 mW at 852 nm for cesium. This result highlights the promising nature of such laser system especially for Cs manipulation for which no fiber laser system has been reported. It offers new perspectives for the development of atomic instruments dedicated to onboard ap…
We present a narrow linewidth continuous laser source with over 11 Watts of output power at 780nm, based on single-pass frequency doubling of an amplified 1560nm fibre laser with 36% efficiency. This source offers a combination of high power, simplicity, mode quality and stability. Without any active stabilization, the linewidth is measured to be below 10kHz. The fibre seed is tunable over 60GHz, which allows access to the D2 transitions in 87Rb and 85Rb, providing a viable high-power source for laser cooling as well as for large-momentum-transfer beamsplitters in atom interferometry. Sources …
We report on the study of the noise properties of laser light propagating through a cold 87Rb atomic sample held in a magneto-optical trap. The laser is tuned around the Fg = 2 \rightarrow Fe = 1, 2 D1 transitions of 87Rb. We observe quadrature-dependent noise in the light signal, an indication that it may be possible to produce squeezed states of light. We measure the minimum and maximum phase-dependent noise as a function of detuning and compare these results to theoretical predictions to explore the best conditions for light squeezing using cold atomic Rb.
We present an asymmetric focused-beam trap of rubidium-85 atoms where the cloud volume only varied with the trap laser intensity. By repumping on F=2 to F'=2 D2 transition, the Stokes Raman scattering has strongly affected the population ratio in the two hyperfine ground states. With the volume and trap number simultaneously and separately controlled, we have shown that the cloud density can be monotonously manipulated from zero to the maximum value limited by the cooling power. By solely varying the intensity of repump laser, the scheme for precision loading of exact 1-6 atoms in the FORT, wh…
We present a theory for manipulation of d-wave interaction of cold atoms with two lasers strongly driving two photoassociative transitions. The theory predicts the occurrence of a coherence between two excited ro-vibrational bound states due to the photoassociative dipole-couplings of ground-state d-wave scattering state to the bound states. We show that this excited-state coherence significantly influences atom-atom interaction. In particular, this leads to the enhancement of d-wave elastic scattering and to the suppression of inelastic scattering. In the presence of an s-wave magnetic Feshba…
We propose a mechanism for producing Fock states on demand leaking from a single mode optical cavity interacting with a single atom and a laser pulse. The number of photons can be chosen, as it is determined by the Zeeman substructure of the ground state of the atom and its initial state. The deterministic generation of a free-propagating Fock state of $1\leq n\leq2F$ photons is achieved, when a circularly polarized laser pulse completely transfers the atomic population between Zeeman sublevels of the ground hyperfine state $F$ through far-detuned Raman scattering thus producing linearly polar…
Laser fields can be shaped on a subwavelength scale as to have a specific distribution in spin angular momentum, orbital structure, or topology. We study how these various features affect the strongly nonlinear electron dynamics. Specifically, we derive closed expressions for the wave function of an unbound electron subject to a generally structured, intense laser field and demonstrate its use for imprinting the orbital angular momentum of a propagating optical vortex onto photoelectrons emitted from atoms and traveling through the optical vortex. It is also shown that photoelectrons can be ac…
A quasi-classical model (QCM) of molecular dynamics in intense femtosecond laser fields has been developed, and applied to a study of the effect of an ultrashort `control' pulse on the vibrational motion of a deuterium molecular ion in its ground electronic state. A nonadiabatic treatment accounts for the initial ionization-induced vibrational population caused by an ultrashort `pump' pulse. In the QCM, the nuclei move classically on the molecular potential as it is distorted by the laser-induced Stark shift and transition dipole. The nuclei then adjust to the modified potential, non-destructi…
We experimentally observe the action of multiple light pulses on the transverse motion of a continuous beam of fullerenes. The light potential is generated by non-resonant ultra-short laser pulses in perpendicular spatial overlap with the molecule beam. We observe a small but clear enhancement of the number of molecules in the center fraction of the molecular beam. Relatively low light intensity and short laser pulse duration prevent the molecule from fragmentation and ionization. Experimental results are confirmed by Monte Carlo trajectory simulations.
Experiments in atomic, molecular, and optical (AMO) physics rely on lasers at many different wavelengths and with varying requirements on spectral linewidth, power, and intensity stability. Vertical external-cavity surface-emitting lasers (VECSELs), when combined with nonlinear frequency conversion, can potentially replace many of the laser systems currently in use. Here we present and characterize VECSEL systems that can perform all laser-based tasks for quantum information processing experiments with trapped magnesium ions. For photoionization of neutral magnesium, 570.6$\,$nm light is gener…
Using a semi-classical model to describe the interaction between coherent electromagnetic radiation and a Bose-Einstein condensate in the limit of zero temperature, including the back action of the atoms on the radiation, we have analyzed the phenomenon of emission of solitary-like wave packets which can accompany the formation of mutually localized atom-laser structures.
We report bunching, slowing, and acceleration of a supersonically cooled beam of diatomic hydroxyl radicals (OH). \textit{In situ} observation of laser-induced fluorescence along the beam propagation path allows for detailed characterization of longitudinal phase-space manipulation of OH molecules through the Stark effect by precisely sequenced inhomogeneous electric fields.
Ultracold gases of fermionic alkaline-earth (like) atoms are hopeful candidates for the quantum simulation of many-body physics induced by magnetic impurities (e.g., the Kondo physics), because there are spin-exchange interactions (SEIs) between two atoms in the electronic ground ($^1$S$_0$) and metastable ($^3$P) state, respectively. Nevertheless, this SEI cannot be tuned via magnetic Feshbach resonance. In this work we propose three methods to control the SEI between one atom in the $^1$S$_0$ state and another atom in the $^3$P$_2$ states or $^3$P$_2$-$^3$P$_0$ dressed states, with one or tw…
Superpositions of paraxial Laguerre-Gauss laser beam modes to generate optical potentials based on the optical dipole force are investigated theoretically. Parabolic and other monomial potentials with even powers, in cylindrical and spherical symmetry, with large diameters, can be synthesized. This superposition approach promises to help with high quality atom cloud manipulation and imaging.
Atoms, propagating across a detuned standing laser wave, can be scattered in a chaotic way even in the absence of spontaneous emission and any modulation of the laser field. Spontaneous emission masks the effect in some degree, but the Monte Carlo simulation shows that it can be observed in real experiments by the absorption imaging method or depositing atoms on a substrate. The effect of chaotic scattering is explained by a specific behavior of the dipole moments of atoms crossing the field nodes and is shown to depend strongly on the value of the atom-laser detuning.
