Transition from triggered super-radiance to seed amplification in N lasing.

Air lasing induced by laser filamentation opens a new route for research on atmospheric molecular physics and remote sensing. The generation of air lasing is composed of two processes, i.e.

Sensing Trace-Level Metal Elements in Water Using Chirped Femtosecond Laser Pulses in the Filamentation Regime.

Femtosecond filament-induced breakdown spectroscopy (FIBS) is an efficient approach in remote and in situ detection of a variety of trace elements, but it was recently discovered that the FIBS of water is strongly dependent on the large-bandgap semiconductor property of water, making the FIBS signals sensitive to laser ionization mechanisms. Here, we show that the sensitivity of the FIBS technique in monitoring metal elements in water can be efficiently improved by using chirped femtosecond laser pulses, but an asymmetric enhancement of the FIBS intensity is observed for the negatively and positively chirped pulses. We attribute the asymmetric enhancement to their different ionization rates of water, in which the energy of the photons participating in the ionization process in the front part of the negatively chirped pulse is higher than that in the positively chirped pulse.

In vivo therapeutic effect of wollastonite and hydroxyapatite on bone defect.

The treatment of large-area bone defects is a huge challenge and the current research hot spot is to prepare composite materials to promote the new bone formation. In this study, the rat skull defect was repaired by implanting pure wollastonite and hydroxyapatite composites, which proved that it has a good effect on the treatment of bone defects. 60 SD rats were used as research objects.