The behavior of a RF-excited waveguide CO2 laser in the pulse regime is studied theoretically. The output pulse evolution is studied by applying three types of pulses namely the square, sine and the triangular ones as...The behavior of a RF-excited waveguide CO2 laser in the pulse regime is studied theoretically. The output pulse evolution is studied by applying three types of pulses namely the square, sine and the triangular ones as the excitation pulses. The frequency dependence behavior of the output pulse is also presented.展开更多
The experimental study of the laser beam parameters of the pulse repetitive RF-excited diffusion cooled waveguide CO2 laser are presented.The measurements are carried out for the pumping pulse duration of 100 μs and ...The experimental study of the laser beam parameters of the pulse repetitive RF-excited diffusion cooled waveguide CO2 laser are presented.The measurements are carried out for the pumping pulse duration of 100 μs and pulse repetitive rates 5-14 kHz.The average power density delivered to the active medium is 76 W/cm3.Three types of the pulses,namely the square,the sine and the triangular ones have been applied at the input as pumping pulses and their effects on the output power and the delay time have been studied.The output power of the radiation versus input power,pressure of the laser gas mixture and modulation frequency has been investigated.The results indicate that the output peak power for the three types of pulses increases with increase of the pressure of the laser gas mixture and with the input power where as it decreases with the repetition frequency.The delay time of the output pulse decreases with the increase of the repetition frequency and input power,where as it increases with the increase of the pressure of the laser gas mixture.The behavior of the output power and the delay time with duty cycle for square pulse has also been investigated.展开更多
In this work ITO thin film annealing was carried out using a CW CO2 laser beam for ITO thin film annealing over a 1 cm2 area with a temperature higher than 250°C to obtain ITO grains with excellent structural qua...In this work ITO thin film annealing was carried out using a CW CO2 laser beam for ITO thin film annealing over a 1 cm2 area with a temperature higher than 250°C to obtain ITO grains with excellent structural quality thin films. The obtained ITO films were characterized for crystallization, surface morphology, electrical and optical properties, which has theoretical significance and application value. ITO thin films are deposited on glass substrates by sputter coater system (RF) from a high density target (In2O3-SnO2, 90-10 wt%). After deposition, ITO thin films have been irradiated by CW CO2 laser (λ = 10.6 μm) with power ranging from 1 to 10 watt. These films were annealed at temperatures 250°C, 350°C, and 450°C in the air for 20 minutes using different laser power. The main incentive was to develop a low temperature process for ITO thin films, which typically required a 350°C anneal to crystallize and achieve optimum optical and electrical properties. The XRD results showed that 350°C temperature laser annealing could crystallize ITO with a strong (222) preferred orientation and its grain size increased from 29.27 nm to 48.63 nm. The structure, optical transmission, energy gap, resistivity and sheet resistance of the ITO thin films were systematically investigated as a function of laser post annealing temperature. It was found that the lowest resistivity was 2.9 × 10-4 Ω-cm and that sheet resistance was 14.5 Ω/sq. And the highest optical transmittance (98.65%) of ITO films was obtained at 350°C annealing temperature.展开更多
The design and performance of radio frequency (RF) excited partial Z-fold waveguide CO_2 laser with two channels are exposed. The length of the partial Z-fold channel is 3×460 mm and that of the single channel is...The design and performance of radio frequency (RF) excited partial Z-fold waveguide CO_2 laser with two channels are exposed. The length of the partial Z-fold channel is 3×460 mm and that of the single channel is 460 mm. The electrodes for the two channels are common and excited by a same RF source. According to our analysis, this kind of structure can greatly improve the laser offset frequency stability. In the experiments, we studied the variation of laser output power with gas pressure for two different channels. The maximum laser output power is about 23 W for the partial Z-fold channel and about 6 W for the single channel.展开更多
文摘The behavior of a RF-excited waveguide CO2 laser in the pulse regime is studied theoretically. The output pulse evolution is studied by applying three types of pulses namely the square, sine and the triangular ones as the excitation pulses. The frequency dependence behavior of the output pulse is also presented.
基金Sponsored by National Science Foundation of China(60378010)
文摘The experimental study of the laser beam parameters of the pulse repetitive RF-excited diffusion cooled waveguide CO2 laser are presented.The measurements are carried out for the pumping pulse duration of 100 μs and pulse repetitive rates 5-14 kHz.The average power density delivered to the active medium is 76 W/cm3.Three types of the pulses,namely the square,the sine and the triangular ones have been applied at the input as pumping pulses and their effects on the output power and the delay time have been studied.The output power of the radiation versus input power,pressure of the laser gas mixture and modulation frequency has been investigated.The results indicate that the output peak power for the three types of pulses increases with increase of the pressure of the laser gas mixture and with the input power where as it decreases with the repetition frequency.The delay time of the output pulse decreases with the increase of the repetition frequency and input power,where as it increases with the increase of the pressure of the laser gas mixture.The behavior of the output power and the delay time with duty cycle for square pulse has also been investigated.
文摘In this work ITO thin film annealing was carried out using a CW CO2 laser beam for ITO thin film annealing over a 1 cm2 area with a temperature higher than 250°C to obtain ITO grains with excellent structural quality thin films. The obtained ITO films were characterized for crystallization, surface morphology, electrical and optical properties, which has theoretical significance and application value. ITO thin films are deposited on glass substrates by sputter coater system (RF) from a high density target (In2O3-SnO2, 90-10 wt%). After deposition, ITO thin films have been irradiated by CW CO2 laser (λ = 10.6 μm) with power ranging from 1 to 10 watt. These films were annealed at temperatures 250°C, 350°C, and 450°C in the air for 20 minutes using different laser power. The main incentive was to develop a low temperature process for ITO thin films, which typically required a 350°C anneal to crystallize and achieve optimum optical and electrical properties. The XRD results showed that 350°C temperature laser annealing could crystallize ITO with a strong (222) preferred orientation and its grain size increased from 29.27 nm to 48.63 nm. The structure, optical transmission, energy gap, resistivity and sheet resistance of the ITO thin films were systematically investigated as a function of laser post annealing temperature. It was found that the lowest resistivity was 2.9 × 10-4 Ω-cm and that sheet resistance was 14.5 Ω/sq. And the highest optical transmittance (98.65%) of ITO films was obtained at 350°C annealing temperature.
文摘The design and performance of radio frequency (RF) excited partial Z-fold waveguide CO_2 laser with two channels are exposed. The length of the partial Z-fold channel is 3×460 mm and that of the single channel is 460 mm. The electrodes for the two channels are common and excited by a same RF source. According to our analysis, this kind of structure can greatly improve the laser offset frequency stability. In the experiments, we studied the variation of laser output power with gas pressure for two different channels. The maximum laser output power is about 23 W for the partial Z-fold channel and about 6 W for the single channel.
