Master-oscilltor-amplifier electroionization carbon monoxide laser system and propagation of its radiation through atmosphere

Conclusion Thus, we have created an EI carbon monoxide laser systems, operating by the scheme master-oscillator-amplifier. We have experimentally studied the amplification and absorption of IR (5–6 m) by multilevel active medium of EI CO laser. Conditions of saturated amplification of EI CO laser radiation have been found. By using various methods we have performed the formation of the EI CO laser system spectrum in accordance with atmospheric transparency windows. It should be noted that EI CO laser system with selected spectral lines can be used in laser ranging, laser chemistry, and laser isotope separation.     

A free-electron laser pumped by the soliton laser

We propose a scheme for building a free-electron laser in the soft X-ray region pumped by the soliton laser. Making use of soliton laser wave evolution shape and single-pass small signal analysis, we find that this laser has two special advantages over the previous electromagnetic wave undulator free-electron lasers. One is a very small mass-shift effect because of the special characteristics of soliton laser; the other is that it has an additional frequency tuning effect based on the conventional free-electron laser's tunability. We also obtain the small signal gain and present some discussion.     

Discharge pumped C1F laser at 285 nm

This paper reports on experiments carried out in order to improve the performance of the TEA discharge pumped C1F uv laser at 285 nm. Factors which influence the gas degradation with increasing operating time, resulting in a decrease of laser output power, were investigated, aiming at a better understanding of the relevant mechanisms. By optimizing several parameters, laser pulse energies beyond 25 mJ were obtained in a high-pressure discharge laser chamber. C1F lasing has also been demonstrated in a commercially available multigas TEA laser system.As a byproduct of our C1F experiments, laser action on the correspondingDA transition of Cl₂ at 258 nm has also been achieved for the first time in a discharge laser chamber.     

New FIR Laser Lines from CD3OH

Fourteen new optically pumped far-infrared (FIR) laser lines in the range 46.8 m to 172.6 m were discovered in optically pumped CD₃OH. The pump sources include both the CO₂ laser and the N₂O laser. Two theoretically predicted laser lines were observed in this study.     

The Optimum Operation of an Unified Mini-Optically Pumped NH3 Submillimeter Wave Laser

An unified miniature optically pumped NH₃ submillimeter wave laser (OPSMMWL), including a mini TEA-CO₂ pump laser, was developed. It lased successfully with coherent emission at 67.2m, 90.4m and 151.5m. The optimum operation of the unified mini-OPSMMWL was studied experimentally and the relations among SMMW laser output power, operating gas pressure, length and coupling condition of the cavity were measured. It has been found that buffer gas N₂ has significant effect on 67.2m and 151.5m emissions and very wide band SMMW laser emission was a common feature of the mini-OPSMMW cavity laser.     

Application of Laser Simulation Method for the Analysis of Crater Formation Experiment on PALS Laser

The crater formation process is studied in the laser - Al solid target interactions on the PALS iodine laser facility. A great variety of laser beam parameters are used to irradiate massive aluminium targets. Large laser energies available (up to 600 J) open a possibility to investigate the process of crater formation for physical conditions different from the earlier studies for the lower laser energies. Comparison with the earlier results is presented.A simple theory, LSM (laser simulation method), has been applied for the analysis of the experimental results. This model leads to a universal relation (scaling law) for the crater relative volume. Our work extends the study of crater formation to the virtual macroparticle velocities exceeding 100 km/s. The scaling law is derived here for this previously unexplored region. An alternative method of studying crater formation is also proposed.     

Investigation of XeCl vibrational and quenching kinetics: Measurements of gain and laser spectra in a discharge-pumped oscillator module

The small signal gain, amplified spontaneous emission and laser spectra of a transverse discharge-excited XeCl laser have been measured. Several gas mixtures, total gas pressures and electron densities have been investigated. From these measurements it is concluded, that bound-free transitions and transitions to high-lying vibrational levels of the ground state contribute significantly to the gain and laser emission. For the upper laser level a vibrational population ratio [XeCl(B, =1)]/[XeCl(B, =0)] corresponding to a temperature of about 370 K has been determined. The intensity ratio of about 1 observed for the two laser lines may be explained by the vibrational and quenching kinetics of the lower laser level together with the upper state kinetics. A table summarizing the result of the small gain measurement has been included for model comparison.     

Laser pulse length dependence of internal energy transfer in UV-MALDI-MS

Recent internal energy (IE) measurements for various analytes in matrix-assisted laser desorption ionization (MALDI) have indicated that the amount of IE transferred to analytes not only depends on the matrix but also on the nature of the analyte. Common matrixes, such as -cyano-4-hydroxycinnamic acid (CHCA), 3,5-dimethoxy-4-hydroxycinnamic acid (sinapinic acid, SA), and 2,5-dihydroxy-benzoic acid (DHB), had been characterized as cold or hot according to the IEs of analyte ions produced in the corresponding MALDI plume. In this contribution, we present evidence that IE transfer in MALDI depends on the matrix, analyte, as well as on the laser pulse properties. A substituted benzylpyridinium salt as a thermometer molecule (TM) was investigated in CHCA, SA, and DHB matrixes. A nitrogen laser (4 ns pulse length) and a mode locked frequency tripled Nd:YAG laser (22 ps pulse length) were used as excitation sources at various fluences. Survival yields (SYs) of the analyte molecular ions were extracted from the spectra and the corresponding IEs were obtained from Rice–Ramsperger–Kassel–Marcus (RRKM) theory. The SYs indicate that the IEs of analyte ions in MALDI are analyte, matrix, and laser source dependent. The ion generation threshold fluences follow the same order for both lasers: CHCA<SA<DHB, but for the analyte the mode locked 3× Nd:YAG laser source requires a higher threshold fluence than the nitrogen laser. Despite the higher fluence, the SYs are generally higher (the corresponding IEs are lower) for the 3× Nd:YAG laser than for the nitrogen laser. The SYs of the TM molecular ions decrease with an increase of fluence for both the ns laser and the ps laser. PACS 82.80.Ms; 82.20.Nk; 81.15.Fg     

Ablation of polyimide (Kapton™) films by pulsed (ns) ultraviolet and infrared (9.17 μm) lasers

Ablation of the surface of a polyimide (Kapton) film by single pulses of 248 nm or 308 nm radiation (20 ns) or 9.17 m laser radiation (170 ns) was studied by photographing the emergence of the blast wave and the plume by a pulse (<1 ns; 596 nm) of visible laser light. The dynamics of the blast wave was similar in the ultraviolet and in the infrared but the composition of the plume was obviously different. A mass of opaque solid material was ejected for as long as 2.6 s following the IR pulse in contrast to the minute amount of solids that are seen in the ablation by UV laser pulses of ns duration. UV laser pulses of 50–400 s duration interact with polyimide surfaces in a manner that is similar to IR laser pulses of ns duration or longer. Chemical analysis of the ablation products that are obtained under various conditions of ablation when compared to the known modes of thermal degradation of polyimide show that the reaction is a thermal process when IR laser pulses or UV laser pulses of long (>10 s) duration are employed. Ablation by ns UV laser pulses differs fundamentally in the chemistry of the products from all of the cases mentioned above.     

High spatial intensity 10 W-CuBr laser with hydrogen additives

High beam quality output has been demonstrated from a single medium-scale (2 cm dia. × 50 cm) CuBr laser with hydrogen additives. The addition of hydrogen leads to beam divergence reduction and laser power lift-up finally yielding 5-fold increase in laser power spatial intensity compared with the case of no hydrogen added. With a simple positive-branch unstable resonator practical (pulse-average) divergence of 80 rad is achieved. The easy-feasible sealed-off version of CuBr laser makes it an attractive source for many high-quality laser beam applications.