We demonstrate a new type of four-pass dye laser amplifier that can reduce the possibility of parasitic oscillation between optical components used in the amplifier. Pumping the amplifier with a 5.6-mJ Q-switched doubled Nd:YAG laser output, we obtain high-peak-power pulsed output of an incident cw narrow-bandwidth dye laser beam with a power gain greater than 2 x 10(6) . Subsequent amplificati...

I numerically model broad-bandwidth optical parametric oscillation and amplification to explore the influence of pump bandwidth on conversion efficiency, injection seeding, and generated spectra. I also study narrowbandwidth pumping of broad-bandwidth signal and idler waves. I show that the relative group velocities of the three waves have a critical effect on device performance in all cases an...

In quantum mechanics, the space-fractional Schrödinger equation provides a natural extension of the standard Schrödinger equation when the Brownian trajectories in Feynman path integrals are replaced by Levy flights. Here an optical realization of the fractional Schrödinger equation, based on transverse light dynamics in aspherical optical cavities, is proposed. As an example, a laser implement...

A scheme of Doppler-free spectroscopy is experimentally demonstrated with a co-propagating control laser locking to an atomic hyperfine transition, and the differential transmission of the probe and the reference laser is detected. Crossover resonances are eliminated by selecting the class of atoms with zero velocity in the direction of beam propagation. In addition, the sub-Doppler spectrum ex...

Laser operation of a GaN vertical cavity surface emitting laser (VCSEL) is demonstrated under optical pumping with a nanoporous distributed Bragg reflector (DBR). High reflectivity, approaching 100%, is obtained due to the high index-contrast of the nanoporous DBR. The VCSEL system exhibits low threshold power density due to the formation of high Q-factor cavity, which shows the potential of na...

We demonstrate dynamical nuclear-spin polarization in the absence of an external magnetic field by resonant circularly polarized optical excitation of a single electron or hole charged quantum dot. Optical pumping of the electron spin induces an effective inhomogeneous magnetic (Knight) field that determines the direction along which nuclear spins could polarize and enables nuclear-spin cooling...

The pharyngeal muscles of Caenorhabditis elegans are composed of the corpus, isthmus and terminal bulb from anterior to posterior. These components are excited in a coordinated fashion to facilitate proper feeding through pumping and peristalsis. We analysed the spatiotemporal pattern of intracellular calcium dynamics in the pharyngeal muscles during feeding. We used a new ratiometric fluoresce...

pendence of time-resolved behaviors of another emission in ZnSe thin film at 470 nm. As the excitation power is increased, the faster component of duration less than 1 ps is also increased. This clearly indicates that the fast components are attributed to the stimulated emission from ZnSe under optical-pumping at 400 nm. The time decay and the delay relative to the pumping pulse of the emission...

An overdense plasma layer irradiated by intense light can exhibit dramatic nonlinear-optical effects due to a relativistic mass-effect of free electrons: highly-multiple hysteresises of reflection and transition, and emergence of immobile waves of large amplitude. Those are trapped quasi-soliton spikes sustained by a weak pumping having a tiny fraction of their peak intensity once they have bee...

Lasing is obtained from a two-dimensional (2D) Penrose photonic quasicrystal made of a low index contrast material of holographic polymer dispersed liquid crystals (H-PDLCs) that enables a substantial reduction in the optical pumping threshold. This lasing architecture further allows for excellent linear polarization characteristics as well as wide directional dependence. The pumping threshold ...