Distributions of nitric oxide vibrational temperature, rotational temperature and velocity have been measured in the hypersonic freestream at the exit of a conical nozzle , using planar laser-induced fluorescence. Particular attention has been devoted to reducing the major sources of systematic error that can affect fluorescence temperature measurements, including beam attenuation, transition s...

Nonradiative energy dissipation in electronically excited polyatomic molecules proceeds through conical intersections, loci of degeneracy between electronic states. We observe a marked enhancement of laser-induced double ionization in the vicinity of a conical intersection during a non-radiative transition. We measured double ionization by detecting the kinetic energy of ions released by laser-...

Networks of globally coupled oscillators exhibit phase transitions from incoherent to coherent states. Atoms interacting with the counterpropagating modes of a unidirectionally pumped high-finesse ring cavity form such a globally coupled network. The coupling mechanism is provided by collective atomic recoil lasing, i.e., cooperative Bragg scattering of laser light at an atomic density grating,...

We report the fabrication and operation of a Cr:ZnSe buried channel waveguide laser operating at 2500 nm with a linewidth of 10 nm and a maximum power output of 1.7 W. Ultrafast laser inscription is used to fabricate the depressed cladding waveguide in a polycrystalline Cr:ZnSe sample. A thermal model is developed and predicts performance degradation at higher pump levels due to thermal quenchi...

We propose an alternative method to Q switching for generating giant pulses of laser light in three-level media. This mehod is based on the presence of an external coherent field driving one transition to allow the accumulation of a large population inversion in the other transition without laser oscillation even in a cavity with high-Q factor. The switching off of the external coherent field c...

It has been now well documented that quantum coherence and interference effects can modify the absorption and dispersion properties of an atomic system [1,2]. In the most common situation, that of a Λ-type threelevel system, the medium becomes transparent to a probe laser field near an otherwise absorbing resonant transition. This is achieved via the application of a second laser field coupling...

With a fiber-broadened, femtosecond-laser frequency comb, the 76-THz interval between two laser-cooled optical frequency standards was measured with a statistical uncertainty of 2x10(-13) in 5 s , to our knowledge the best short-term instability thus far reported for an optical frequency measurement. One standard is based on the calcium intercombination line at 657 nm, and the other, on the mer...

Laser plasma accelerators have produced femtosecond electron bunches with a relative energy spread ranging from 100% to a few percent. Simulations indicate that the measured energy spread can be dominated by a correlated spread, with the slice spread significantly lower. Measurements of coherent optical transition radiation are presented for broad-energy-spread beams with laser-induced density ...

We show that the formation of pulses in actively mode-locked lasers exhibits in certain conditions a transition of the laser mode system to a light pulse state that is similar to Bose-Einstein condensation (BEC). The study is done in the framework of statistical light-mode dynamics with a mapping between the distribution of the laser eigenmodes to the equilibrium statistical physics of noninter...

We have applied a combination of laser excitation and electric-field detachment to negative atomic ions for the first time, resulting in an enhancement of the excited-state detection efficiency for spectroscopy by at least 2 orders of magnitude. Applying the new method, a measurement of the bound-bound electric-dipole transition frequency in (192)Os- was performed using collinear spectroscopy w...