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.     

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.     

Computer solution for the traveling-wave-excited N2laser

A computer solution is presented for the nitrogen laser excited by a longitudinal relativistic electron beam. The solution demonstrates efficient extraction by amplified spontaneous emission, and preferential radiation parallel to the electron beam, caused by the traveling-wave nature of excitation. These observations tend to validate approximations used to calculate extraction in an earlier study.     

Compact high-power N2laser: Circuit theory and design

Based on measurements of the transient voltage across the cavity of a transversely excited N2laser an equivalent circuit is developed which provides better understanding of the contribution of all individual components to maximum peak power. Consideration of the design criteria established guarantees about one million light pulses with more than 1 MW from simple high-efficiency construction.     

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.     

The infrared N2laser as a pump for IR dyes

An infrared molecular nitrogen laser cooled by liquid nitrogen was used to pump a simple grating tuned infrared dye laser in the wavelength range from 0.915 μm to 1.04 μm. Broad-band operation of the dye lasers produced efficiencies as high as 20 percent, and produced output at wavelengths as long as 1.096 μm.     

Behavior of first- and second-positive emission in the N2/SF6laser

Experimental results for the behavior of the emission of the discharge-excited first- and second-positive bands of N2and flow-tube measurements for the deactivation of theA^{3}Sigmamin{u}max{+}andB^{3}Pi_{g}levels of N2by SF6are presented. The results of both these experiments are used to explain the operating mechanisms of the N2/SF6laser.     

CO2laser preamplifier capabilities for low-level 10.6-µm direct-detection receivers

We examine the potential of CO2laser preamplifiers for sensitivity enhancement in low-level, direct-detection 10.6-μm receivers. For the condition in which a gain-dependent competition exists between the background noise and amplifier spontaneous emission noise (assuming negligible thermal noise), the analysis predicts an optimum useful SNR enhancement of only 6 dB for a blackbody background field of 300 K and 4.1 dB for a background of 260 K, when the amplifier gain bandwidth perp-line is 100 MHz and the infrared (IR) filter bandwidth is 0.10 μm. Based on preselected choice of gain and bandwidth, a two-stage, water-cooled, flowing-gas amplifier of optimized design was constructed. A maximum gain of 3.12 dB was attained forP(20)with a He : CO2: N2mixture of 5.0 : 1.0 : 0.6 at a coolant temperature of 285 K and a slow gas refresh rate of 0.2 volumes/s. Using a fast-flow system with 12-volume/s refresh rate, we measured an amplifier gain of 3.9 dB, close to the design estimate of 4.1 dB. With a calibrated HgCdTe detector,f/4cold shield, and narrow-band (0.25 μm) cold filter, a spontaneous emission flux density ofsim 1.0 times 10^{14}photons/ cm². s was measured at the 3.12-dB gain level, in close agreement with the theoretical estimate. Excess noise resulting from amplifier discharge was undetectable above the basic detector noise.     

Investigation of a Q-switched pulsed discharge CO2laser

AQ-switched pulsed discharge CO2laser is investigated and the dependence of peak power on delay between pulse excitation andQswitching is determined for different gas mixtures. Peak power of 5 kW with 13 percent efficiency is obtained.     

On the observation of the Λ-doubling in the O - O UV N2laser band

The spectral composition of the (O-O) N2UV stimulated band, as the linewidths of the individual stimulated transitions remain unchanged when the nitrogen pressure and the excitation voltage range from 40 to 100 torr and, from the threshold, to 10 kV, respectively, is observed with a laboratory superradiant emitter.     

A theoretical description of the 5106-Å pulsed copper vapor laser

A theoretical model that accounts for the experimentally observed features of the 5106-Å pulsed copper vapor laser has been devised. The electron excitation and ionization cross sections used in the theory were calculated by the use of the classical Gryzinski-type methods.     

3547-Å pumped parametric oscillation in RD*A

Efficient parametric oscillation in a deuterated rubidium dihydrogen arsenate (RD*A) crystal has been achieved by pumping with the third harmonic of a Nd: YAG laser. A peak power as high as 1.2 MW at 7095 Å and peak powers in excess of 0.5 MW from 6470 to 7850 Å have been obtained.     

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.     

An investigation of the effects of the discharge parameters on the performance of a TEA N2laser

The effects of the discharge parameters on laser performance have been studied experimentally and theoretically in a TEA N2laser driven by a Blumlein circuit. Unmeasurable circuit constants such as the resistance and the inductance of discharge plasma are derived by circuit analysis, and the dependence of the laser output energy on the discharge parameters is discussed in terms of the theoretical quantity which denotes the figure of merit of the discharge circuit.     

A study of the spontaneous emission from CO2-N2-He-H2laser discharges C3πu-B3πgemission bands of N2

Results of spectroscopic investigations of the spontaneous emission of CO2lasers are presented. The band head emission in the Second Positive System (C^{3}pi_{u}- B^{3}pi_{g}) of N2is studied as a function of discharge current and laser output power. The observed changes of the band head intensities are described in terms of the vibrational energy distribution in theC^{3}pi_{u}electronic state of N2. A simple model is developed by which the influence of the laser process can be understood. The excitation properties of theC^{3}pi_{u}state are in reasonable qualitative agreement with the predictions of this model.     

Mode-locking of an atmospheric pressure cross-excited electrically pulsed CO2laser

Self-mode-locking of a cross-excited electrically pulsed CO2laser has been observed and studied as a function of cavity length and operating pressure. The best results are obtained at a pressure of 450 torr with cavity lengths on the order of 1m. Two-ns duration pulses have been measured, the shortest pulses observed to date at 10.6-μ wavelength. With longer cavities more axial modes are locked, resulting in a longer dead time between pulses; however, the pulsewidths increase with increasing cavity length. Mode-locking was not improved by the use of the bleachable absorber SF6.     

Tunable picosecond pulse generation by an N2laser pumped self Q-switched distributed feedback dye laser

The temporal characteristics of a distributed feedback dye laser are investigated both theoretically and experimentally. It is shown that the feedback is provided by the gain modulation and that the effect of refractive index modulation is negligible. The solution of the coupled rate equations predicts the generation of picosecond pulses. The mechanism of short pulse formation is selfQ-switching which differs fundamentally from mode locking. A novel experimental arrangement for pumping the distributed feedback laser is described which makes it possible to obtain transform-limited pulses even with a partially coherent pumping source such as the N2laser. The experimental results show excellent qualitative and satisfactory quantitative agreement with the computer solutions. A very simple and reliable method for generation of tunable, nearly transform-limited single pulses with 36 ps duration (FWHM) is demonstrated experimentally. The feasibility of picosecond and subpicosecond pulse generation in the entire visible and near IR region is discussed.     

CW 10.6-µ CO2laser pumped by the chemical reaction of nitric oxide with nitrogen atoms

The operation of a CW CO2laser pumped by vibrationally excited nitrogen generated by the reaction of nitric oxide with atomic nitrogen is reported. 15-mW output power at an overall chemical efficiency of 1 percent has been obtained. The population inversion density of the system has been determined from gain measurements.