In this paper we first report on a continuous wave laser diode end-pumped passively Q-switched Tm,Ho:YLF laser at 2053 nm with Cr:ZnS crystal as a saturable absorber near room temperature. The pulsewidth is very stable at about 1.25 µs, the pulsed energy is about 4 µJ, and the pulse repetition is between 1.3 and 2.6 kHz when the pump power is changed from 1.0 to 1.9 W. The nearly diffraction-limited and stable long pulse laser can be used to laser lidar systems for accurate wind velocity measurements. Normalized intensity1.0

Based on the model of continuous wave end-pumped quasi-three-level system, the influence of energy transfer upconversion (ETU) on diode-end-pumped actively Q-switched Tm, Ho : YLF lasers is investigated by the rate equation analysis. The analytical expressions of the fractional thermal loading and the pulse energy are obtained. The influences of ETU on the fractional thermal loading and the output pulse energy are analysed. The theoretical results show that the ETU reduces not only the pulse energy but also the effective upper level lifetime of the actively Q-switched Tm, Ho : YLF laser. The practical example of the diode-end-pumped Q-switched Tm, Ho : YLF laser has been used to verify the present model.

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Abstract.Edible oil quality is related to people healthy,existing technology can't realize the convenient and fast detection.This paper studied on the basis of the interdigital capacitance sensor,based on the dielectric constant measurement principle ,used to detect edible oil electrical parameter.Useing capacitance AD7746 digital conversion chip,at the same time AD7746 utilizes I 2 C serial interface protocol and communicates with micro controller PIC18F452 single chip, achieving capacitance data acquisition and processing,form a shortcut edible oil detection system of high accuracy in real time.

The optical bistability of Tm,Ho:YLF laser is theoretically investigated based on the rate equation theory model in this paper. The optical bistability output is obtained by numerical simulation, and the influence of energy transfer upconversion on the bistability behavior is analyzed. Furthermore, the formation scheme of optical bistability is also discussed by the relation between the gain and the loss. The theoretical analysis shows that the saturation of ground state reabsorption and energy transfer upconversion effect are necessary to the optical bistability of Tm,Ho:YLF laser.