Optimal control theory is applied to design a laser pulse to produce an anisotropic change of the refraction index in the vicinity of the isotropic-nematic phase transition in liquid crystals. The laser induced birefringence originates from the orientational anisotropy induced by the laser eld that is enhanced signiicantly due to the excluded volume eeect. The shape of the optimal pulse is anal...

We present studies of resonance-enhanced photo-ionization for isotope-selective loading of Ca into a Paul trap. The 4s S0 ↔ 4s4p P1 transition of neutral calcium is driven by a 423 nm laser and the atoms are photo-ionized by a second laser at 389 nm. Isotope-selectivity is achieved by using crossed atomic and laser beams to reduce the Doppler width significantly below the isotope shifts in the ...

The spectral properties of single molecules placed near a metallic surface are investigated at low temperatures. Because of the high quality factor of the optical resonance, a laser-induced shift of the molecular lines is evidenced for the first time. The shift dependence on the laser excitation intensity and on the dephasing rate of the transition dipole is studied. A simple theoretical model ...

We have produced laser-cooled crystals of 232Th3+ in a linear rf Paul trap. This is the first time that a multiply charged ion has been laser cooled. Our work opens an avenue for excitation of the nuclear transition in a trapped, cold 229Th3+ ion. Laser excitation of nuclear states would establish a new bridge between atomic and nuclear physics, with the promise of new levels of metrological pr...

An optically pumped tunable HBr laser has been demonstrated for the first time. The pump source was a single-frequency Ho:YLF laser and amplifier system, which was locked to the 2064 nm absorption line of HBr. Laser oscillation was demonstrated on 19 molecular transition lines, which included both the R-branch (3870-4015 nm) and the P-branch (4070-4453 nm), by the use of an intra-cavity diffrac...

Laser-induced fluorescence (LIF) measurements have been performed for the first time in a low temperature (Te approximately 0.6 eV) Xe plasma using a tunable diode laser in the visible range of wavelengths. The transition in Xe II involved the (3P1)5d[3]7/2 metastable state and the excitation wavelength was found to be 680.570+/-0.001 nm (air). LIF measurements of I 2 in a room temperature iodi...

We synthesized tunable far-infrared radiation at frequencies higher than 9 THz (300 cm (-1)) by mixing CO(2) laser, (15)NH(3) laser, and microwave radiation in a W-Co metal-insulator-metal diode. We used this farinfrared radiation to accurately measure torsion-rotation transitions of CH(3)OH in the 8-9-THz region. We also measured the frequency of the aP(7, 3) (15)NH(3) laser transition.

The photon statistics of the light emitted from an atomic ensemble into a single field mode of an optical cavity is investigated as a function of the number of atoms. The light is produced in a Raman transition driven by a pump laser and the cavity vacuum, and a recycling laser is employed to repeat this process continuously. For weak driving, a smooth transition from antibunching to bunching i...

Spectral measurements of visible coherent transition radiation produced by a laser-plasma-accelerated electron beam are reported. The significant periodic modulations that are observed in the spectrum result from the interference of transition radiation produced by multiple bunches of electrons. A Fourier analysis of the spectral interference fringes reveals that electrons are injected and acce...

New radiative-lifetime measurements based on time-resolved laser-induced fluorescence are reported for 133 odd-parity and 2 even-parity levels of Co I, ranging in energy from 28 300 to 59 400 cm–1. Our lifetimes agree with earlier, but much less extensive, lifetime measurements based on laser-induced fluorescence. Satisfactory agreement is also found with the critical compilation of atomic tran...