Mg doped ZnO (MZO) thin films were prepared by magnetron sputtering and laser induced breakdown spectroscopy (LIBS) were characterized by Q-switched nanosecond 1064nm Nd:YAG laser pulse. Element characteristic spectral lines from MZO thin films with Mg concentration of 0.1 at%, 0.26 at% and 0.49 at% are illustrated by LIBS system. The results show that Mg (I) emission lines are observed corresponding the relatively high excitation with increasing Mg doped concentration. It can be mainly interpreted as more crystallization planes produced by high Mg doping concentration radiate different atomic spectral lines. The results are in relative agreement with XDR patterns. We calculated the electron density of 8.08×1022 cm-3, 7.70×1022 cm-3 and 7.99×1022 cm-3 inferred by measuring the Starkbroadened line profile. The electron temperature of 21875.85 K, 42941.49K and 28985.51K was determined using the Boltzmann plot method through the acquired data.
Plasma produced by the radiation of a 1064 nm Nd:YAG laser focused onto a standard aluminum alloy E311 was studied spectroscopically. The electron density was inferred by measuring the Stark broadened line profile of Cu I 324.75 nm at a distance of 1.5 mm from the target surface with the laser irradiance of 3.27 GW/cm2. The electron temperature was determined using the Boltzmann plot method with eight neutral iron lines. At the same time, the validity of the assumption of local thermodynamic equilibrium was discussed in light of the results obtained.
A chalcogenide glass was used for an optical Kerr gate to sampling pulse contrast of femtosecond lasers with low repetition rate ( 40 Hz). The dynamic range of this method reached 103, with a scanning range of 150ps and temporal sampling rate of 6.3 fs. The advantage of this method lies in its broad spectrum range including visible and NIR spectral region and easy operation.
Due to its breakthrough the electro-optical time response limitation for picosecond dynamics of processes, many research
groups around the world operating in different fields from physics and chemistry to biology, medicine and material science,
utilize laser setups capable of providing subpicosecond pulses and femtosecond-level time delay lines. However
the signal amount of Femto-picosecond Dynamics is about at an altitude of 1%, but the fluctuation of femtosecond probe
pulse at its best can only reach about 5%. Real-time correct the probe pulse is the only effective way to realize
subpicosecond time-resolved detection precision of transient absorption spectroscopy. So in this paper, reference pulse
was drawn into the measurement equipment through different methods to dispel the fluctuation of probe pulse. Firstly, in
the case of Subpicosecond time-resolved transient absorption spectroscopy, probe and reference beams have the same
spectral distribution and derived from the same source to measure the variation of transmittance in the excited volume.
Secondly probe pulse is spatially and temporally overlapped to the excitation pulse, reference pulse spatially overlapped
but temporally anticipated in respect to the excitation pulse. Finally reference pulse passes through the sample in a
different position. The detector can be a CCD camera or a double photodiode. The results shown that when reference
pulse passes through the sample in a different position and detected by CCD, the correction results can reach to 1%.
Which meet the femto-picosecond dynamics precise requirement.
ZnSe/SiO2 silica gel glasses were prepared through a sol-gel process. A femtosecond transient absorption spectroscopy and a time-resolved photoluminescence spectroscopy were used to detect the electron and hole relaxation in the ZnSe QDs. In the case of excitation 3.76eV, the TA and PL spectra were detected. The results showed that two competing processes, electron-hole recombination and surface electron trapping, occur in 10~100 ps time scale and the holes on valance band decay in about 1 ps.