相关论文: Measurement of delayed fluorescence in N2+ with st…
We perform high resolution spectroscopy of $N_2^+$ emission in light filaments using a controlled pump at 795 followed by a second harmonic weak probe. Our result suggests that transient gain is achieved by resonant stimulated Raman…
We report the development and detailed calibration of a multiphoton fluorescence lifetime imaging system (FLIM) using a streak camera. The present system is versatile with high spatial (0.2 micron) and temporal (50 psec) resolution and…
We demonstrate a novel method to measure the temporal evolution of electric fields with optical frequencies. Our technique is based on the detection of transient currents in air plasma. These directional currents result from sub-cycle…
The axial dependence of femtosecond filamentation in air is measured under conditions of varying laser pulsewidth, energy, and focusing f-number. Filaments are characterized by the ultrafast z-dependent absorption of energy from the laser…
The increasing availability of high-power Yb-based ultrafast laser-amplifier systems has opened the possibility of air filamentation at high repetition rates >1 kHz. In this new regime, accumulation effects cannot be ruled out, therefore,…
Accidental exposure to overdose ionizing radiation will inevitably lead to severe biological damage, thus detecting and localizing radiation is essential. Traditional measurement techniques are generally restricted to the limited detection…
We revisit the time-resolved photoemission in neon atoms as probed by attosecond streaking. We calculate streaking time shifts for the emission of 2p and 2s electrons and compare the relative delay as measured in a recent experiment by…
Attosecond streaking of atomic photoemission holds the promise to provide unprecedented information on the release time of the photoelectron. We show that attosecond streaking phase shifts indeed contain timing (or spectral phase)…
In this work, we propose a novel method for continuous real-time measurement of the dynamics of the nonlinear refractive index n2. This is particularly important for characterizing phenomena or materials (such as biological tissues, gases…
Streaked photoemission metrology allows the observation of an apparent relative time delay between the detection of photoelectrons from different initial electronic states. This relative delay is obtained by recording the photoelectron…
The femtosecond laser filamentation is the result of the dynamic interplay between plasma self-focusing and defocusing generated by the multiphoton/tunnel ionization of air molecules. This equilibrium allows the filament to stably propagate…
We report the cell biological applications of a recently developed multiphoton fluorescence lifetime imaging microscopy system using a streak camera (StreakFLIM). The system was calibrated with standard fluorophore specimens and was shown…
FRET measurements can provide dynamic spatial information on length scales smaller than the diffraction limit of light. Several methods exist to measure FRET between fluorophores, including Fluorescence Lifetime Imaging Microscopy (FLIM),…
Solar storms can have a major impact on the infrastructure of the earth. Some of the causing events are observable from ground in the H{\alpha} spectral line. In this paper we propose a new method for the simultaneous detection of flares…
The scattering of light impacts sensing and communication technologies throughout the electromagnetic spectrum. Overcoming the effects of time-varying scattering media is particularly challenging. In this article we introduce a new way to…
The generation of a streaking spectrogram is based on energy absorption from the streaking laser. Investigating this absorption we show rigorously under which condition the measured time shift is independent of properties of the streaking…
Air lasing provides a promising technique to remotely produce coherent radiation in the atmosphere and attracts continuous attention. However, the polarization properties of N2+ lasing with seeding has not been understood since it was…
Ionization of an atom or molecule by a strong laser field produces sub-optical cycle wave packets whose control has given rise to attosecond science. The final states of the wave packets depend on ionization and deflection by the laser…
Several matrix approaches were developed to control light propagation through multiple scattering media under illumination of ultrashort pulses of light. These matrices can be recorded either with spectral or temporal resolution. Thanks to…
According to a recent experiment, the instantaneous electronic Kerr effect in air exhibits a strong intensity dependence, the nonlinear refractive index switching sign and crossing over from a self-focusing to a de-focusing nonlinearity. A…