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Stimulated THz emission from intra-excitonic 3p to 2s transitions in Cu2O is directly observed by ultrafast opto-electronics. The process occurs at a photon energy of 6.6 meV, with a cross section of ~10-14 cm2.
Femtosecond time-resolved photoelectron spectroscopy has been used to measure the electron-phonon coupling constant of free size selected Nan+ (n=16-250) clusters. The extrapolated electron-phonon coupling constant of bulk sodium is gB sime 2:3 times 1016 W/m3K.
In ultra-intense ultrafast laser-matter interaction, the interplay of laser-induced oscillating space-charge fields with laser E- and B-fields can strongly affect whether the interaction is relativistic or not; with increasing intensities, relativistic character may saturate.
Ultrafast reorientation of the antiferromagnetic order parameter of NiO is triggered by a photoinduced transient modification of the magnetic anisotropy and evidenced by the subsequent interference of the hard- and easy-axis states.
We show theoretically how electrical and pure spin AC currents can be optically injected in semiconductors via excitation of continuum carriers. The electrical current should be observable by detecting its THz radiation.
Femtosecond pulses coupled to hollow-pyramid near-field probes allow achieving sufficient peak power to perform near-field nonlinear optics. We present second-harmonic generation images of nanostructured metal surfaces with spatial resolution better than 100 nm.
Pulses from an ultrafast oscillator are conditioned, amplified, and delivered in an all-optical-fiber architecture. Combined with an electro-optic receiver, the complete system delivers a 4-V electrical trigger with less than 400 fs additive jitter.
This paper deals with the microstructure of the generated crystals in borate glass by femtosecond laser irradiation, Raman spectroscopy was used to study the distribution of the two phases of barium metaborate crystals produced.
We experimentally observed the self-distortion of picosecond pulses propagating in silicon wire waveguides. The asymmetry of output pulse shape was due to two-photon absorption generated free carriers within the pulse duration.
Sub-10-fs visible pulses allow real time detection of coherent phonons in single-walled carbon nanotubes. Nonlinear coupling between radial breathing (250 cm-1) and the carbon-stretching (1600 cm-1) modes is experimentally observed and theoretically modeled.
Time-resolved mid-infrared pump-probe measurements in a quantum cascade laser operating above threshold reveal gain recovery dynamics to be two-fold: relaxation within a stage on a sub-picosecond scale and transport between stages on a picosecond scale.
We present a contrast filter reaching 12 orders of magnitude from micro to milliJoule input pulse with 24% efficiency. It solves contrast issue for Petawatt class lasers in microjoule seeded CPA or double CPA scheme.
We investigate the fabrication of dielectric components for surface plasmon polariton (SPP) processing by two-photon polymerization of photosensitive materials on metal surfaces. SPP guiding and focussing will be demonstrated using near- and far-field optical microscopy.
Dipole-dipole interactions between Rb atoms at internuclear distances 100-1000 Aring are probed at noncryogenic conditions, based on femtosecond laser parametric four wave mixing and wavepacket modulation. Theoretical analysis of the novel results is offered.
We demonstrate three-dimensional imaging by wide field optical coherence tomography with high-speed CMOS camera. A sample volume of 2.3times2.3times1.1mm3 (corresponding to 256times256times300 pixels) was imaged at 10 volumes/s by the scanning reference mirror.
A synchronously pumped, fs-OPO with automated tuning in combination with an optimized scanner / microscope / detection system is used for MPE- and SHG microscopy on biological samples. The system and first results are presented.
We have demonstrated a beam scanning multi-photon multi-harmonic endoscope based on a flexible fiber bundle. Excited by a femtosecond Cr:Forsterite laser, multi-photon multi-harmonic excitation efficiencies are recovered without any external devices.
The intensity-related carrier-envelope phase dynamics of octave-spanning Ti:sapphire lasers is investigated. Taking the laser gain dynamics into account, quantitative agreement between the measured and predicted carrier-envelope phase noise resulting from pump laser noise is achieved.
A channel waveguide exhibiting internal gain under pumping is fabricated inside erbium doped oxyfluoride-silicate glass using a femtosecond laser. The waveguide cross section and refractive index contrast is controlled using a multi-scan technique.
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