Raman shifting of tunable ArF excimer laser radiation in a mixture of H(2) and D(2) produces tunable radiation in the 224-nm region as a result of Stokes shifting the frequency of the fundamental radiation (193 nm) once in both H(2) and D(2). At a total pressure of 25 bars, a 19% H(2) in D(2) mixture is found to provide a maximum conversion efficiency (2.5%) to the 224-nm range. Both fundamenta...

A laser line-scanning instrument was developed to optimize the near-field enhancement capability of a one-dimensional photonic crystal (PC) for excitation of surface-bound fluorophores. The excitation laser beam is shaped into an 8 μm × 1 mm line that is focused along the direction of the PC grating, while remaining collimated perpendicular to the grating. Such a beam configuration offers high ...

the possibility of terahertz generation has been investigated from a photoconductive switch based on gaas, gated by a femtosecond laser. the emission properties of photoconductive antenna (pca) with low-temperature-grown (lt) gaas have been studied. in such gaas materials presence of the charged defects induces a redistribution of the electric field between the antenna electrodes. this effect h...

We analyze the spin dynamics of an individual magnetic atom (Mn) inserted in a II-VI semiconductor quantum dot under resonant optical excitation. In addition to standard optical pumping expected for a resonant excitation, we show that for particular conditions of laser detuning and excitation intensity, the Mn spin population can be trapped in the state which is resonantly excited. This effect ...

The methods producing cold molecules from cold atoms tend to leave molecular ensembles with substantial residual internal energy. For instance, cesium molecules initially formed via photoassociation of cold cesium atoms are in several vibrational levels nu of the electronic ground state. We applied a broadband femtosecond laser that redistributes the vibrational population in the ground state v...

Rotational excitation and spatial alignment in moderate intensity radiation fields are studied numerically and analytically, using time-dependent quantum mechanics. Substantial rotational excitation is found under conditions typically used in time-resolved spectroscopy experiments. The broad rotational wave packet excited by the laser pulse is well defined in the conjugate angle space, peaking ...

Photomagnetic storage and retrieval of information in the megahertz frequency range utilizes a ferrimagnetic material as the storage medium in conjunction with parametric excitation of infrared exchange resonance spinwave modes, by means of signal-modulated polarized coherent radiation, for example, from a COz laser at 10.6 micrometer length, focused to the storage medium. Parametric excitation...

We report on the coherent phonon spectroscopy of polymorphic MoTe2 single crystals using a femtosecond-pulsed laser to investigate relationship between structural phase transitions and photo-thermal effects induced by high-density excitation. Even when femtosecond pulsed was used, which generally induces fewer heat accumulation than case for CW laser, tellurium segregation observed in spectra w...

Fluorescence correlation spectroscopy (FCS) could provide a more useful tool for intracellular studies and biological sample characterization if measurement times could be reduced. While an increase in laser power can enable an autocorrelation function (ACF) with adequate signal-to-noise to be acquired within a shorter measurement time, excitation saturation then leads to distortion of the ACF ...

INTRODUCTION Blue-green 488-nm laser sources are widespread in flow cytometry but suffer some drawbacks for cell analysis, including their excitation of endogenous proteins (resulting in high cellular autofluorescence) and their less-than-optimal coincidence with the excitation maxima of commonly used fluorochromes, including the phycoerythrins (PE). Longer wavelength lasers such as green heliu...