A TE duolaser providing simultaneous lasing on CO2and N2O transitions

Simultaneous laser action on CO2and N2O transitions has been achieved in a helical resistor-pin-type transversely excited (TE) laser. The laser emits typically a power of 10-100 kW in a 700-ns-long pulse which consists basically of two overlapping pulses, the peaks of which do not coincide, and which can be associated with the CO2and N2O emission, respectively. The conditions of optimal operation are described and the effects of some parameter changes are indicated.     

PassivelyQ-switched N2O laser

Freon 12 and SF6have been used to passivelyQswitch laser transitions fromR(17)toP(36)in the00deg1-10deg0N2O band. Pulses having a half-intensity width of 0.75 μs with peak powers 10-20 times the CW power were observed.     

Pulsed N2O molecular laser studies

The afterglow pulse-gain technique was used to measure the relaxation of the 00°1 upper laser level in N2O from 300 to 700°K. The rate constantk_{N_{2}O}(torr^-1s^-1) varies with temperature aslog10k_{N_{2}O} = 4.53 - 10.9T^{-1/3}. Measurements of the relaxation time at 300°K agree with the fluorescence technique results of Yardley [1]. Gain studies were also made with gas mixtures in a nonflowing system. Single-pulsed N2O + CO + He mixtures at 300°K showed considerable peak gain. However, subsequent pulses of these mixtures show that the gain is reduced because of the chemical reaction forming CO2. Measurements of this transformation from one molecular laser mixture to another are discussed.     

Optical pumping by CO2and N2O lasers: New CW FIR emissions in 1,1-difluoroethane

53 new CW FIR laser lines are reported in 1,1-difluoroethane optically pumped near 10 μm by CO2and N2O lasers. The emission spectrum initially reported in the literature consisted of four lines between 770 and 458 μm and has now been extended to the 2.39 mm- 319 μm region. The reason for this extension, especially to the long wavelengths, is analyzed.     

Direct optical pumping of high-pressure CO2and N2O lasers with a pulsed HF pump laser

Pulsed HF laser radiation has been used for direct optical excitation of CO2and N2O lasers at 10 and 5 atm gas pressures, respectively, which are the pressures required for continuous laser frequency tuning between the line centers in these gases. The maximum demonstrated quantum efficiency is about 14 percent, which seems to be limited by the formation of pressure waves in the gas, in addition to losses in the resonator optics. We find that quantum efficiencies close to unity are theoretically feasible with a low-loss resonator, and by using a sufficiently short pump pulse to avoid a serious influence from pressure waves. The excitation scheme can be used with any of the CO2and N2O laser isotopes.     

Third-harmonic generation in a mixture of DBr and N2O

Third-harmonic generation of CO2P(24) 10.6 mum laser radiation was achieved in a mixture of DBr and N2O. The ratio of DBr and N2O used was 29:1. A frequency tripled signal was observed up to a total pressure of 4 atm.     

Collisionally induced lasing in CO2and N2O using vibrationally excited CO

Continuous-wave oscillation has been observed on a number of P-branch transitions belonging to the     

Higher order harmonics of CO2and N2O laser difference frequencies

The generation of the fourth and fifth harmonics of the difference frequency between two 28-THz laser lines, by a tungsten-nickel diode, was observed.     

Active mode locking of a high-pressure pulsed N2O laser

Experimental results on the active mode locking of a transversely excited N2O laser at subatmospheric pressures are presented. Nanosecond pulses of 10.8-μ radiation were produced with typical peak-power outputs in the 100-kW range.     

Near single-line operation of a free-burning CS2/O2/N2O flame laser with a nondispersive optical cavity

The CS2/O2/N2O flame laser has been operated for the first time under conditions in which the spectral output is nearly single line. This transition is theP_{10-9}(17) of CO at 5.4265 μm, the same transition which was observed to oscillate in single-line fashion by Hirose et al. in an electrically initiated CO chemical laser. It is suggested that the unique behavior of this line may be due to its close proximity to aPbranch transition in an adjacent band, namely theP_{9-8}(23) line, such that the gain profiles of the two lines overlap. Calculations suggest that at the conditions of these experiments, the separation of the line centers for this pair is about 0.3 Å or less. TheP_{10-9}(17) transition was also found to be totally absent under certain conditions of high multiline power, particulary at low O2and N2O flows. This may be due to absorption by a high-bandRbranch transition at 5.4266 μm, namely theR_{15-16}(32) line.     

Lasing in N2O and CO2isotope mixtures pumped by blackbody radiation

The use of N2O and CO2isotopes as active species for a blackbody radiation pumped laser has been experimentally demonstrated and theoretically analyzed. The results obtained for mixtures containing N2O,¹³C¹⁶O2, and¹²C¹⁸O2are presented. For the first time, continuous lasing action with blackbody radiation pumping has been obtained for this species. Two active species mixtures were tested, obtaining up to a 100 percent increase in output power due toupsilon-upsilontransfer. A simple model was developed and gain calculations are presented.     

Laser parameters for the 10.8-µ N2O molecular laser

Measurements were made of the radiative lifetime for the 001-100 transition in N2O, the absolute population densities of the laser levels, and the saturation parameter in a typical flowing N2O-N2-He laser. These numbers are compared with the corresponding parameters in the CO2-N2-He system to explain the difference in their performance characteristics. In addition, dissociation of N2O in a discharge and power enhancement in the N2ON2-He laser by adding CO are discussed.     

Organic lasers excited by a pulsed N2laser

Laser action was obtained from rhodamine 6G and sodium fluorescein solutions by transverse pumping with a pulsed nitrogen laser. Relatively high efficiencies were observed and the threshold powers required were low. A repetition rate of ∼70 Hz was achieved with modest pump powers.     

Long-pulse N2UV lasers at 357.7, 380.5, and 405.9 nm in N2/Ar/Ne/He mixture

Using long-pulse electron-beam pumping, long-pulse laser emissions at 357.7, 380.5, and 405.9 nm have been observed in the second positive system of nitrogen with pulse durations of 150, 400, and 400 ns, respectively. Substantial improvements in laser performance were observed by adding excess Ne and He into N2+ Ar mixtures. Peak powers of 56, 44, and 66 kW/cm²have been obtained for the three wavelengths, respectively.     

A stacked Blumlein N2laser

A novel device for producing fast-rise-time, large-volume electrical-discharge excitation of gas lasers is described. Some operating characteristics of an N2ultraviolet (UV) laser are presented.     

The F + H2O chemical laser

Laser oscillation, restricted by energy limitations to transitions from first vibrationallevel to ground state, has been observed from HF produced by the reaction of the F atom on H2O initiated by pulsed electric discharge in flowing mixed F2-H20-He gases at 10 torr.     

Gas dynamic CO2-He-(N2) laser investigations

Experiments on IR laser action and gain measurements are reported for a CO2-containing gas mixture flow that cools as a result of expansion. The mixture is preheated by a reflected shock wave, and the gas is expanded into a vacuum through a slit. Laser action is obtained in a CO2-He mixture, while the addition of nitrogen increases the gain. The gain was found to depend on the distance from the slit and the gas pressure before the slit.     

Pulsed discharge initiated chemical lasers -- Part II: HF laser emission from NF3and N2F4systems

A transverse, multiple-arc pulsed discharge has produced laser emission in NF3and N2F4mixed with H2, CH4, C2H6, HCl, HBr, and natural gas.P_{10}, P_{21}, P_{32}, and P43HF transitions were observed. The peak powers measured ranged from ∼8.5 to 25 kW with typical pulsewidths ofsim0.3 mus.     

The identification of candidate transitions for optically pumped far infrared lasers: Methyl halides and D2O

Two hundred and forty-four candidate transitions for optically pumped far infrared lasers have been identified in C¹²H3F, C¹³H3F, C¹²D3F, C¹²H3Cl³⁵, C¹²H3Cl³⁷, C¹²H3Br⁷⁹, C¹²H3Br⁸¹, and D2O using as candidate pump lines, 781 in number, the isotopic forms of CO2, the sequence and hot bands of C¹²O2¹⁶, and the N2O bands. The dominant transition parameters responsible for strong emission from TEA, CW, and long pulse modes of operation were identified by a correlation between known experimental behavior and the pertinent transition parameters, the results being that strong TEA laser emission correlates with ground state population while strong CW and long pulse emission correlate with absorption coefficient. The candidate transitions were subsequently selected on the basis of these parameters using calculated transitions and assignments based on band data from high resolution laser-Stark spectroscopy and measured candidate pump frequencies.