A two-photon transition in cold Rb atoms will be probed with a phase-coherent wide bandwidth femtosecond laser comb. Frequency domain analysis yields a high-resolution picture where phase coherence among various transition pathways through different intermediate states produces interference effects on the resonantly enhanced transition probability. This result is supported by the time domain Ra...

We report on a terahertz spectrometer for high-resolution molecular spectroscopy based on a quantum-cascade laser. High-frequency modulation (up to 50 MHz) of the laser driving current produces a simultaneous modulation of the frequency and amplitude of the laser output. The modulation generates sidebands, which are symmetrically positioned with respect to the laser carrier frequency. The molec...

The dependence of the lasing threshold on the amount of positional disorder in photonic crystal structures is newly studied by means of the finite element method, not of the finite difference time domain method usually used. A two-dimensional model of a photonic crystal consisting of dielectric cylinders arranged on a triangular lattice within a circular region is considered. The cylinders are ...

The interest in random fiber lasers (RFLs), first demonstrated one decade ago, is still growing and their basic characteristics have been studied by several authors. RFLs are open systems that present instabilities in the intensity fluctuations due to the energy exchange among their non-orthogonal quasi-modes. In this work, we present a review of the recent investigations on the output characte...

The saturation spectrum of the P(84) 5-5 transition of 127I2 at 657.483 nm is obtained with the third-harmonic demodulation method using an external cavity diode laser. The laser frequency is modulated by modulating the diode current instead of modulating the cavity length with a piezoelectric transducer (PZT). Current modulation allows a modulation frequency that is higher than PZT modulation....

We demonstrate a technique for directly measuring the fine-structure interval in alkali atoms using two frequency-stabilized diode lasers. Each laser has a linewidth of order 1 MHz and precise tunability: one laser is tuned to a hyperfine transition in theD1 line, and the other laser to a hyperfine transition in the D2 line. The outputs of the lasers are fed into a scanning Michelson interferom...

Near the condition of electromagnetically induced transparency in a three-level system, the absorption experienced by the weak probe laser beam interacting with one transition is very sensitive to the frequency detuning of the strong-coupling laser beam coupled to another transition. When the frequency detuning of the coupling laser is modulated at different frequencies, the resulting change in...

An integrated Laser Ablation Fluid RAdiation simulation Code (LAFRAC) has been developed to estimate behaviors of highly energetic ions and neutral particles from laser produced plasmas, and to estimate ionization and recombination processes. Neutral particles cannot be controlled by electric and/or magnetic forces. Therefore, estimation of the number of neutral particles and mitigation of them...

We present results on a Raman laser-system that resonantly drives a closed two-photon transition between two levels in different hyperfine ground states of (87)Rb. The coupler is based on a novel optical design for producing two phase-coherent optical beams to drive a Raman transition. Operated as an outcoupler, it produces an atom laser in a single internal atomic state, with the lower diverge...