Saturation of the molecular nitrogen second positive laser transition

A review of the status of research towards achieving lasing action in the vacuum ultraviolet and soft X-ray spectral regions is presented. An analysis of the general problems likely to be encountered is accompanied by numerical results for those approaches currently considered promising. Progress on each approach is detailed and various possible methods of verifying the presence of gain with their relative merits are discussed. Research areas requiring Application of short-wavelength lasers also are given.

Review of short wavelength laser research

Stimulated emission has been observed in the $P$ -branch lines of the 3-10, 4-11, 5-12, 6-13, and 7-13 Lyman bands (${v}^{\ensuremath{'}}\ensuremath{-}{v}^{\ensuremath{'}\ensuremath{'}}$, $B^{1}{\ensuremath{\Sigma}}_{\mathrm{u}}^{+}\ensuremath{\rightarrow}X^{1}{\ensuremath{\Sigma}}_{g}^{+}$) of molecular hydrogen near 1600 \AA{}. Light pulses of approximately 2 nsec duration and 1.5 kW maximum power were produced using a Blumlein parallel-plate transmission line discharging through hydrogen gas at pressures between 20 and 150 Torr.

Vacuum-ultraviolet laser action observed in the Lyman bands of molecular hydrogen

High-resolution Fourier spectrometry of 14 N 2 infrared emission spectrum: Extensive analysis of the B 3 Π g - A 3 Σ u + system

Rate coefficients, as a function of the electron temperature, have been determined from the integral cross sections for excitation of the 19 singlet and triplet electronic states of N2 within 14.2 eV of the ground state. For electron temperatures less than 10 eV, the rates for excitation of the A 3Σ+u, B 3Πg, W 3Δu, and a 1Πg are all greater than that for excitation of the C 3Πu state. The differential cross sections for excitation of these same electronic states were also used to calculate the inelastic momentum transfer associated with the excitation of these states. The total momentum transfer cross section for electrons in N2, as a function of the electron energy, was obtained by adding the inelastic momentum transfer to that associated with elastic scattering. Inelastic momentum transfer accounts for about 25% of the total momentum transfer above 15 eV. Over the energy range 20–60 eV, inelastic scattering contributes 20–25% to the total N2 electron scattering cross section. The total scattering cross section obtained here is in good agreement with a recent direct measurement of this cross section.

Rate coefficients and inelastic momentum transfer cross sections for electronic excitation of N2 by electrons

Accurate wavelength measurements in the molecular nitrogen pulsed laser have been made. Four new ir laser bands were discovered. In addition, about two hundred new stimulated emission lines belonging to the first and second positive systems were obtained and identified as to rotational quantum number. An analysis of the possible pumping mechanisms in accordance with experimental results is given.

Investigation of a pulsed molecular nitrogen laser at low temperature.

Spectroscopic techniques have made possible the observation and ionic assignment of unclassified xenon laser lines.

Ionic assignment of unidentified xenon laser lines

Analysis of recent observations of the Xe III spectrum has yielded revised and extended identifications for the 5s25p3(4S)6s, 7s, 6p, 5d, 6d and 4f levels. Four of the previously known twenty-two levels have been rejected whereas sixteen new levels have been added. The ionization energy has been determined from isoelectronic comparisons. The value arrived at, 250 400 ± 300 cm-1, is some 9000 cm-1 lower than the presently accepted value.

https://iopscience.iop.org/article/10.1088/0031-8949/19/5-6/008/pdf

C. A. Massone

Papers

Investigation of a pulsed molecular nitrogen laser at low temperature.

Ionic assignment of unidentified xenon laser lines

5s2 5p3 (4S)nl Levels of Xe III

Superradiant and Laser Spectroscopy in the Second Positive System of N 2

On the interaction between the first and second positive laser systems in N2