Slab CO2 lasers excited by switching power

In this paper we present a new discharge technique to excite slab CO₂ lasers. A uniform stable glow discharge has been obtained in a volume of 3 × 30 × 446 mm³. Output power is 10 W, and a gain of 0.26% cm⁻¹ has been obtained.     

The Gravitational Field of a Circulating Light Beam

Exact solutions of the Einstein field equations are found for the exterior and interior gravitational field of an infinitely long circulating cylinder of light. The exterior metric is shown to contain closed timelike lines.     

ABCD矩阵方法在主动锁模光纤激光器理论与实验分析中的应用

应用ABCD矩阵方法从理论上对主动锁模环形光纤激光器进行了分析并与实验结果进行了比较.     

Spectral characteristics of 2 μm microchip Tm:YVO4 and Tm,Ho:YLF lasers

In this paper, we present experimental results concerning the spectral emission obtained with two microchip lasers emitting in the 2 μm range. We show that high efficiency is achieved in both cases at room temperature. Nevertheless, while Tm:YVO₄ oscillates always on longitudinal modes and may easily be single frequency with high power, Tm:Ho:YLF is always emitting several transverse modes for any pumping conditions with temperatures between 13°C and 35°C. This result is interpreted considering the gain of these two amplifier media and the mode guiding resulting from the thermal properties of the two host materials.     

A Microchip Tunable Blue Laser Source Based upon Cr:LiSAF in Contact with KN Crystal

In this paper, a microchip laser consisted of 2.2% doped Cr:LiSAF crystal and NCPM KN(KNbO3) crystal and pumped by a 679 nm laser diode is reported. The maximal output of TEM00 4.76 mW of blue laser at 431.7 nm is obtained with the absorption power of 304.6 mW. The laser shows a threshold of 76.2 mW and slope efficiency of 2.08%. Continuous-wave tunable output is demonstrated in the blue region of 423.4～445.5 nm through only changing temperature of KN crystal controlled by PID controller.     

A parametric study of negative feedback Nd:YAG laser

The output pulse parameters of a mode-locked Nd:YAG laser with a passive negative feedback element were studied experimentally. The pulse evolution within the train was experimentally recorded using a modified second harmonic generation autocorrelator. By comparing the laser operation with and without an acousto-optic modulator, we found that with the later there is a significant increase in the mode locking probability and the pulse acquires a temporally Gaussian symmetric pulse shape. Further with the active modulator there is a relaxation in alignment tolerances and increase in the range of permissible dye concentrations for stable mode locking. It was also observed that the pulse width of the negative feedback laser depends on the saturation intensity of the mode locking dye and reduces for a dye with higher saturation intensity. The pulse width was also found to reduce linearly as the initial transmission of the dye is reduced.     

Photoacoustic detection of NO2 traces with CW and pulsed green lasers

Photoacoustic NO₂ traces detection based on continuous and pulsed lasers emitting at 532 nm is presented. Both systems were calibrated with known NO₂-pure air mixtures. A minimum detectable volume concentration of 20 parts in 10⁹ (S/N=1) and 15 parts in 10⁹ for the resonant and pulsed regime, respectively, were obtained. These values were limited by electrical and acoustical noise of the microphone and electronics. Measurements of NO₂ concentrations in urban air are compared with home-manufactured mixtures. Traces of nitrogen dioxide from two different car exhausts are also detected and quantitatively assigned from the calibration curves.     

Noise Like Ultra-Short Bound Solitons Train

Asymmetrical bound solitons train with pulsewidth of 103fs and separation of 585.5fs without any CW components are observed from Figure-8 passive mode locked fiber laser, the separation and pulsewidth keep unchanged even after 1.2Km SMF.     

激光二极管抽运的GaAs被动Q开关Nd∶YVO4激光器

利用固体可饱和吸收体砷化镓 (GaAs)作为被动调Q元件 ,实现了激光二极管抽运平凹腔掺钕钒酸钇(Nd∶YVO4)激光调Q运转 ,详细测量了砷化镓被动调QNd∶YVO4激光输出特性 ,获得脉宽 15ns,重复频率 4 70kHz,光束质量M2 =1.31的激光输出 ,调Q激光运转阈值为 5 0 0mW ,并数值求解了砷化镓被动调Q速率方程 ,讨论了被动调Q机理以及调Q脉冲宽度和脉冲重复频率对抽运速率的依赖关系 ,理论计算结果与实验结果相一致。     

Multi-wavelength generation of L-band brillouin/erbium fibre laser

In this paper, the operation of the Brillouin/erbium fibre laser (BEFL) in the long wavelength band (L-band or 1565–1625 nm) is experimentally demonstrated. The Stokes frequency is shifted 10 GHz from its Brillouin pump (BP) from 1598 to 1612 nm for the single wavelength BEFL. Multiple wavelength generation in the BEFL is realised by adding two 3-dB couplers, which are joined in a reverse-S arrangement to take a portion of the generated BEFL signal and re-inject it into the single-mode fibre (SMF) to seed a cascaded BEFL line in the same direction as the first BEFL line. Twenty lines including the anti-Stokes are obtained with a maximum BP and 980-nm pump power of 8.8 and 92 mW, respectively. The L-band BEFL has the potential to be used in future wavelength division multiplexing (WDM) communication system.