Many-electron dynamics of a Xe atom in strong and superstrong laser fields

We report on detailed investigations of ionization dynamics of a Xe atom exposed to intense 800-nm pulses of 20-fs duration in the extensive intensity range from 10(13)-10(18) W/cm(2). Ion yields of Xe+-Xe20+ were observed as a function of laser intensity and compared with the results from a single active electron based Ammosov-Delone-Krainov model. Unexpected ionization probabilities for lower charge states and no interplay between the inner and outer shells by screening are inferred. Suppression of nonsequential ionization towards higher intensity and few optical cycle regimes is also proved.     

Development of three-dimensional microfabrication method using thermo-sensitive resin

We have developed a three-dimensional microfabrication method using thermo-sensitive resin. This method exploits the fact that polymerization of thermo-sensitive resins does not obey the law of linear superposition. Three-dimensional (3D) objects are created inside the thermo-sensitive resin by 3D scanning of the volume with a focused laser. Fabrication with the focus of the laser inside the resin can achieve good accuracy and high resolution of the structure. A fabrication system, which consisted of a CD-R pick-up laser and an XYZ stage, was built. Nonlinear polymerizations of the thermo-sensitive resin were verified by fabrication in various conditions of laser intensity and exposure time. In order to demonstrate the present method, a simple 3D microstructure was fabricated inside the resin. PACS 42.62.Cf; 42.70.Jk; 42.82.Cr     

Two-color chirped-pulse amplification in an ultrabroadband Ti:sapphire ring regenerative amplifier

We have developed a high-energy, ultrabroadband Ti:sapphire ring regenerative amplifier capable of producing in excess of 20-mJ output at a 10-Hz repetition rate. The technique of chirped-pulse amplification is used to generate two-color, time-synchronized pulses with central wavelength separations of up to approximately 120 nm and with a total energy of 10 mJ by use of a regenerative pulse-shaping technique. Mid-infrared pulses tunable from 6 to 11 microm are generated by difference frequency mixing the two-color outputs.     

360-W average power operation with a single-stage diode-pumped Nd:YAG amplifier at a 1-kHz repetition rate

We report a high-average-power laser-diode-pumped Nd:YAG master oscillator power amplifier system that has a minimum number of elements in the single multipass zigzag-slab amplifier stage and is used to pump a high-peak-power and high-average-power Ti:sapphire laser system. This phase-conjugated system produces an average power of 362 W at 1 kHz in a 30-ns pulse with an optical-to-optical conversion efficiency of 14%. With an external KTP doubler this system generates 132 W of green average output power at 1 kHz with a conversion efficiency of 60% when pumped at a power level of 222 W. To the best of our knowledge these results represent the highest average output power at both infrared and green wavelengths achieved in a single amplifier stage.     

Stereoselective pinacol coupling of chiral formylferrocene using divalent samarium triflate: preparation of a new chiral bisferrocenyl oxazoline ligand and its application to asymmetric Diels-Alder reactions

[reaction: see text] The pinacol coupling reaction of planar chiral ortho-oxazoline-substituted formylferrocene was smoothly mediated by SmI2 or Sm(OTf)3 to give the (R,R) isomer selectivity (up to 76% diastereomeric excess). The combination of Yb(OTf)3 and the (R,R)-ferrocenyl diol was revealed to be a good catalyst for the asymmetric Diels-Alder reaction of 3-acyloxazolidinone with cyclopentadiene, and the endo adduct was produced in up to 80% enantiomeric excess.     

Palladium-catalyzed cyanoesterification of norbornenes with cyanoformates via the NC-Pd-COOR (R = Me and Et) intermediate

[reaction: see text] Palladium-catalyzed cyanoesterification of norbornenes proceeds stereoselectively via NC-Pd-COOR (R = Me and Et) complexes as intermediates.