Demonstration of a transient-gain nickel-like xenon-ion x-ray laser

We demonstrate a high-gain nickel-like xenon-ion x-ray laser, using a picosecond-laser-irradiated gas-puff target. The elongated x-ray laser plasma column was produced by irradiation of the gas-puff target with line-focused double picosecond laser pulses with a total energy of 18 J in a traveling-wave excitation scheme. Strong lasing at 9.98 nm was observed, and a high gain coefficient of 17.4 cm(-1) was measured on the transient collisionally excited 4d-4p , J=0-1 transition for nickel-like xenon ions with target lengths as great as 0.45 cm. A weak nickel-like lasing line at a shorter wavelength of 9.64 nm was also observed, with a gain coefficient of 5.9 cm(-1) .     

激光调制和激光通信原理的演示

给出了一种演示激光调制和激光通信原理的电路设计。     

Demonstration of supercontinuum generation in a long-cavity fiber ring laser

We demonstrate generation of supercontinuum pulses directly from a passively mode-locked long-cavity fiber ring laser. The laser output exhibited a blueshifted spectrum extending from 1350 to 1550 nm with an average output power greater than 60 mW.     

激光加热液体薄膜的演示

介绍用干涉方法定性观察激光加热液体薄膜的实验，该实验仪器简单，操作方便。     

半导体泵浦射流型亚稳态氩激光国际首次出光北大核心CSCD

半导体泵浦亚稳态惰性原子激光是高能光泵浦气体激光领域具有潜力的新方案。已有报道均在约束的放电空间内产生亚稳态原子,功率放大受到多因素制约。为突破现有方案的局限,采用大气压等离子体射流方式在羽流区域产生高浓度亚稳态氩原子(1014 cm^(−3)量级),将放电和激光区域空间分离,利用811 nm窄线宽半导体激光器作为泵浦源,基于泵浦、激光和气流相互垂直的结构实现912 nm激光输出,有效拓展了该型激光体系的功率定标放大能力。     

双色激光偏振演示实验

利用红色和绿色激光束产生2束偏振方向分别平行及垂直于入射面的偏振光,再混合为1束光.通过缓慢改变光束的偏振结构及其与入射透明介质的夹角,使反射与透射光斑颜色及明暗发生变化,演示了马吕斯定律、菲涅耳关系和布儒斯特定律等光的偏振性质.     

Demonstration of a neonlike argon soft-x-ray laser with a picosecond-laser-irradiated gas puff target

We demonstrate a neonlike argon-ion x-ray laser, using a short-pulse laser-irradiated gas puff target. The gas puff target was formed by pulsed injection of gas from a high-pressure solenoid valve through a nozzle in the form of a narrow slit and irradiated with a combination of long, 600-ps and short, 6-ps high-power laser pulses with a total of 10 J of energy in a traveling-wave excitation scheme. Lasing was observed on the 3p (1)S(0)?3s (1)P(1) transition at 46.9 nm and the 3d (1)P(1)?3p (1)P(1) transition at 45.1 nm. A gain of 11 cm(-1) was measured on these transitions for targets up to 0.9 cm long.     

Demonstration of a collisionally excited optical-field-ionization XUV laser driven in a plasma waveguide

We describe the first demonstration of a collisionally excited optical-field-ionization laser driven within a waveguide. Lasing on the 4d(9)5d-4d(9)5p transition at 41.8 nm in Xe8+ was observed to be closely correlated to conditions under which the pump laser pulses were guided well by a gas-filled capillary discharge waveguide. Simulations of the propagation of the pump laser radiation show that gain was achieved over essentially the whole 30 mm length of the waveguide.     

Demonstration of a Ni-like Kr optical-field-ionization collisional soft x-ray laser at 32.8 nm

We report the first experimental demonstration of a Ni-like optical-field ionization collisional soft x-ray laser. The amplifying medium is generated by focusing a circularly polarized 760 mJ, 30 fs, 10-Hz Ti:sapphire laser beam in a few mm cell filled with krypton. We have measured a gain coefficient of 78 cm(-1) on the 3d(9)4d 1S0-3d(9)4p(1)P1 transition at 32.8 nm, which is here amplified for the first time. This radiation source represents the shortest wavelength optical-field ionization collisional soft x-ray laser ever produced. The influence of the gas pressure and the pumping energy on the lasing output are also presented.     

Demonstration of a compact 100 Hz, 0.1 J, diode-pumped picosecond laser

We have demonstrated an all-diode-pumped Yb:YAG chirped pulse amplification laser that produces 100 mJ pulses of 5 ps duration at 100 Hz repetition rate. The compact laser system combines a room-temperature Yb:YAG regenerative amplifier for increased bandwidth and a cryogenically cooled Yb:YAG four-pass amplifier for improved heat dissipation and increased efficiency. The optical efficiency of this amplifier is higher than that of other diode-pumped systems of comparable energy.     

Demonstration of a 10-muJ tabletop laser at 52.9 nm in neonlike chlorine

We report the demonstration of laser amplification at 52.9 nm in Ne-like Cl with a compact capillary discharge. Laser output pulses with energies of as much as 10 muJ have been obtained. The beam divergence was approximately 4 mrad. This new 23.4-eV tabletop laser is of particular interest for applications that require high peak fluxes of photons with energy slightly below the He photoionization threshold.     

Demonstration of optical synchronization of chaotic external-cavity laser diodes

An experimental demonstration of optical synchronization of chaotic external-cavity semiconductor laser diodes is reported for what is believed to be the first time. It is shown that at an optimum coupling strength between the master and the slave lasers high-quality synchronization can be obtained.     

Sulfur determination on stone monuments with a transportable EDXRF system

An important part of the world's cultural heritage is represented by stone monuments. A very dangerous weathering process that deteriorates stone monuments and is caused by human activity is air pollution. One of the worst pollutants for stone monuments is associated with sulfur compounds, especially with gypsum. Gypsum is a rather soluble compound that may be washed away by rain. It leaves the surface of the stone clean but eroded and open to new corrosive processes. With transportable energy dispersive x‐ray fluorescence (EDXRF) instruments it is possible to conduct in situ investigations, mappings, registrations and evaluations of the stone‐degradation phenomena related to sulfate formation on stone and stone‐like materials by quantifying sulfur concentrations directly associated with the presence of gypsum. The EDXRF instrument used in this project is a commercial system comprising a miniaturized low‐power, air‐cooled tungsten x‐ray tube and a silicon drift detector (SDD) Peltier‐cooled detector. The EDXRF instrument was calibrated using a series of standard samples specifically developed for this project with a sulfur content ranging from 0.5 to 15%. Correlating the sulfur peak counts with sulfur concentrations, a straight calibration line (R² = 0.9985) was obtained. Several high voltage levels of the x‐ray tube were tried to define the best operating conditions. The silicon escape peak of calcium had to be accounted for owing to its interference with the sulfur peak. In this paper we shall discuss the working method adopted and the results achieved following the examination of a number of stone monuments such as the “Fanciulla di Anzio” and other ancient Roman statues housed in the Roman National Museum, and the Sarcophagus of Pope Boniface VIII sculpted by Arnolfo di Cambio and situated in the Crypt of the Vatican Basilica. Copyright © 2007 John Wiley & Sons, Ltd.     

Demonstration of microwave frequency shifting by use of a highly chirped mode-locked fiber laser

We report an experimental demonstration of a photonic microwave shifter using a highly chirped mode-locked fiber laser. The system is based on dispersive compression or expansion of highly chirped optical pulses that are amplitude modulated by the microwave signal. Using this technique, we demonstrated frequency shifting of a microwave signal from 10 GHz down to 5 GHz and up to 25 GHz.     

Demonstration of an all-optical switch by use of a multiwavelength mutual injection-locked laser diode

Error-free all-optical packet switching is demonstrated by use of a multiwavelength mutual injection-locked Fabry-Perot laser diode. A 10-Gbit/s data signal is switched on and off with an extinction ratio of 16.9 dB when an optical control signal is turned off and on with a power difference of only 3 dB.     

Demonstration of a nine lines distributed feedback dye laser using three pairs of pump beams

Controllable, maximum nine-wavelength operation of a wavefront divided, multiple beam pumped, distributed feedback dye laser (DFB), is reported for the first time. Equally spaced three to nine lines have been obtained by pumping a dye solution with three pairs of excitation beams derived from the same source. Experimental results lead to a nine line model of a distributed feedback dye laser (DFDL). The dye cell was excited by the 2nd harmonic of a laboratory built, cavity dumped, passively q switched and mode-locked Nd:YAG laser, to induce a temperature phase grating in the dye solution. Different features studied included threshold conditions, simultaneous induction of multiple gratings, impact of pump polarizations, and temporal and spectral characteristics of the emitted lines. This work on the DFDL is in agreement with most of the published results on semiconductor DFB lasers [1, 2, 3] and opens a new era of research. This multi-wavelength operation of a DFDL is based on the nonlinear effects of an overwritten multiple dynamic grating on a R6G dye solution in ethanol. PACS 42.60.By     

Demonstration of a widely tunable digital supermode distributed Bragg reflector laser as a versatile source for near-infrared spectroscopy

In this paper we report the characterization of a novel, widely tunable, diode laser source operating over the full telecom L-band (1563–1613 nm), namely the digital supermode distributed Bragg reflector (DS-DBR) laser, and its application to multi-wavelength gas sensing via absorption strategies. The spectroscopic performance of the laser has been assessed by investigating the ro-vibrational spectrum of CO₂, and wavelength modulation spectroscopy was accomplished for proof-of-principle sensitive measurements in discrete spectral regions.