We propose a fiber-solid hybrid system which consists of a semiconductor saturable absorber mirror(SESAM)modelocked fiber seed with a pulse width of 10.2 ps and a repetition rate of 18.9 MHz,a two-level fiber pre-ampl...We propose a fiber-solid hybrid system which consists of a semiconductor saturable absorber mirror(SESAM)modelocked fiber seed with a pulse width of 10.2 ps and a repetition rate of 18.9 MHz,a two-level fiber pre-amplifier and a double-passing end-pumped Nd:YVO4 amplifier.In the solid-state amplifier,to enhance the gain and the extraction efficiency,a specially designed structure in which the seed light passes through the gain medium four times and makes full use of population inversion is used as the double-passing amplifier.Besides,the beam filling factor(the ratio of the seed light diameter to the pump light diameter)and the thermal lens effect of the double-passing amplifier are considered and its optical-to-optical conversion efficiency is further improved.To preserve the beam quality of the double-passing amplifier,a new method of spherical-aberration self-compensation based on the principles of geometrical optics is used and discussed.Our system achieves a maximum average power of 9.5Wat the pump power of 28W,corresponding to an optical-to-optical efficiency of 27%.And the beam quality factor M^2 reaches 1.3 at the maximum output power.展开更多
A fast and simple method for determination of α, β, γ-hexachlorocyclohexanes (HCHs) in water using activated carbon fiber-solid phase microextraction(ACF-SPME) were studied. Results showed the performance of adsorp...A fast and simple method for determination of α, β, γ-hexachlorocyclohexanes (HCHs) in water using activated carbon fiber-solid phase microextraction(ACF-SPME) were studied. Results showed the performance of adsorption and desorption of three HCHs on ACF were excellent. A wide linear range from 10 to 100 μg/L and detection limits of the ng/L level were obtained using ACF-SPME with GC-MS in selected ion monitoring(SIM) acquisition mode. The proposed method was also successfully applied for determination of three HCHs in tap water. Compared to commercial fibers, ACF showed some advantages such as better resistance to solvents, higher thermal stability, longer lifetime and lower cost. The data demonstrated that GC-MS with ACF-SPME is well suitable for the analysis of HCHs in water.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61675009 and 61325021)Key Program of Beijing Municipal Natural Science Foundation,China(Grant No.KZ201910005006).
文摘We propose a fiber-solid hybrid system which consists of a semiconductor saturable absorber mirror(SESAM)modelocked fiber seed with a pulse width of 10.2 ps and a repetition rate of 18.9 MHz,a two-level fiber pre-amplifier and a double-passing end-pumped Nd:YVO4 amplifier.In the solid-state amplifier,to enhance the gain and the extraction efficiency,a specially designed structure in which the seed light passes through the gain medium four times and makes full use of population inversion is used as the double-passing amplifier.Besides,the beam filling factor(the ratio of the seed light diameter to the pump light diameter)and the thermal lens effect of the double-passing amplifier are considered and its optical-to-optical conversion efficiency is further improved.To preserve the beam quality of the double-passing amplifier,a new method of spherical-aberration self-compensation based on the principles of geometrical optics is used and discussed.Our system achieves a maximum average power of 9.5Wat the pump power of 28W,corresponding to an optical-to-optical efficiency of 27%.And the beam quality factor M^2 reaches 1.3 at the maximum output power.
文摘A fast and simple method for determination of α, β, γ-hexachlorocyclohexanes (HCHs) in water using activated carbon fiber-solid phase microextraction(ACF-SPME) were studied. Results showed the performance of adsorption and desorption of three HCHs on ACF were excellent. A wide linear range from 10 to 100 μg/L and detection limits of the ng/L level were obtained using ACF-SPME with GC-MS in selected ion monitoring(SIM) acquisition mode. The proposed method was also successfully applied for determination of three HCHs in tap water. Compared to commercial fibers, ACF showed some advantages such as better resistance to solvents, higher thermal stability, longer lifetime and lower cost. The data demonstrated that GC-MS with ACF-SPME is well suitable for the analysis of HCHs in water.
