Xiaomei Yang

Widely tunable PPLN/IOPO driven by a diode-end-pumped Q-switched Nd:YVO4 laser

This paper reported a broadband tuning intracavity optical parametric oscillator (IOPO), based on the multiple grating periodical poled lithium niobate (PPLN) pumped by a acoustic-optical (AO) Q-switched Nd:YVO4 laser. The widely tunable OPO output signal wavelength range from 1390 to 1605 nm, which was obtained by changing PPLN poling period from 27.8 to 31.6 μm at a certain temperature of 46°C, while the continuous tuning range was measured from 1475 to 1592 nm with the PPLN poling period of 30 μm by varying the temperature of nonlinear crystal PPLN from 50 to 120°C. The maximum output power of 0.92 W at 1534 nm with the minimum pulse width of 5.17 ns was generated under the incident pump power of 9.6 W at 808 nm. The corresponding peak power and single pulse energy were calculated to be 5.94 kW and 30.7 μJ, respectively. The M2-factor was measured to be 2.01 at the signal power of 0.4 W.

1.3-ns pulse, compact passively Q-switched microchip green laser by Nd:YAG/Cr4+:YAG composite crystal

In this article, a diode-end-pumped passively Q-switched extra-cavity frequency doubled micro-type green laser by Nd:YAG/Cr4+:YAG composite crystal was demonstrated. The dependence of the average out power, pulse width and pulse repetition rate on incident pump power were measured. Under the pump power of 14 W, the minimum pulse width of 1.3 ns with repetition rate of 68.0 kHz was obtained, corresponding single-pulse energy of 8.8 μJ and peak power of 6.7 kW.

The pulse reshaping characteristics of V:YAG in passively Q-switched Nd:YVO4/Cr:YAG laser at 1064 nm

The pulse reshaping characteristics of V:YAG in a 1064-nm Cr:YAG Q-switched laser have been demonstrated. The pulse duration is compressed by as much as 55% in contrast to Cr:YAG solely Q-switched lasers. The minimum pulse duration is 28 ns with the pulse repetition rate of 98 kHz. The stability and symmetry of the pulses are also obviously improved. The results shows V:YAG is a potential reshaping element for 1-μm pulses.

A compact, widely tunable intracavity PPLN optical parameter oscillator driven by an Nd:YAG/Cr:YAG composite crystal laser

Based on periodically poled lithium niobate (PPLN), a mini intracavity optical parameter oscillator (IOPO) driven by an diode-end-pumped composite Nd3+:YAG/Cr4+:YAG laser was demonstrated. The PPLN wafer has 20 domain reversal periods from 27.8 to 31.6 μm with a step of 0.2 μm between the neighbor periods. The output signal laser of OPO can be widely tunable in the range of 1402–1676 nm by changing the period at a certain temperature of 50°C. Under the diode pump power of 14 W, the maximum average output power of 600 mW at 1534 nm with pulse width of 2.0 ns and repetition rate of 16 kHz was obtained, corresponding to a peak power of 18.7 kW and a single pulse energy of 37.5 μJ, respectively.

High serum selenium levels are associated with impaired fasting glucose and elevated fasting serum glucose in Linyi, China

BACKGROUND The relationship between selenium level and impaired fasting glucose or elevated fasting serum glucose remains controversial. This study aimed to evaluate these associations in China. METHODS This observational population study adopted a cluster sampling approach to enroll participants. Baseline information on selenium categories was tested using one-way analysis of variance and Kruskal-Wallis equality-of-populations rank tests. Multivariable logistic regression was used to investigate the association between serum selenium level and impaired fasting glucose or elevated fasting serum glucose. RESULTS The mean serum selenium concentration was 121.5μg/L which in a relatively high baseline Se status. Differences were observed among individuals with normal, impaired fasting glucose and elevated fasting serum glucose levels in their basic information, physical examination results and laboratory findings. After adjusting for their basic information, physical examination results and laboratory findings, compared with the low-selenium group, the high-selenium groups (124.9-143.9 and above 143.9μg/L) had ORs for elevated fasting serum glucose of 2.31 (1.37-3.90) and 2.67 (1.59-4.48), respectively (both P<0.05). A sex-difference was observed, and a significant association between selenium levels and impaired fasting glucose was observed for males but not for females. CONCLUSIONS The findings of this observational study suggest that relatively high selenium levels might be positively associated with elevated fasting serum glucose and relatively high selenium levels might be positively associated with impaired fasting glucose in men.