Armin W. Tucker

Stimulated‐emission cross section at 1064 and 1342 nm in Nd : YVO4

The stimulated‐emission cross sections at 1064 (4F3/2→4I11/2) and 1342 nm (4F3/2→4I13/2) in Nb : YVO4 were determined by measurement of laser thresholds as a function of output mirror reflectivity. Small samples of Nd : YVO4 and Nd : YAG were end pumped at room temperature with a cw 514.5‐nm argon ion laser in an almost identical geometrical arrangement which permitted comparative values to be obtained. Assuming that the pumping quantum efficiency of Nd : YVO is similar to that of Nd : YAG, the stimulated‐emission cross sections obtained for the 1064‐ and 1342‐nm transitions were respectively 12×10−19 and 6.0×10−19 cm2.

Continuous‐wave operation of Nd : YVO4 at 1.06 and 1.34 μ

Continuous‐wave plane‐polarized outputs of 1 W at 1.06 μ and 0.35 W at 1.34 μ were obtained by end pumping small samples of Nd : YVO4 with an argon‐ion laser. Slope efficiencies and material losses were determined. At 1.06 and 1.34 μ, Nd : YVO4 lasers can substantially outperform Nd : YAG lasers. Self‐Q‐switched operation of Nd : YVO4 at both wavelengths was obtained by resonator misalignment.

Laser emission cross section of Nd:YAG at 1064 nm

The stimulated emission cross section of Nd:YAG (yttrium aluminum garnet) (4F3/2→4I11/2) was compared to the known cross section of Nd:ED‐2 glass at 1060 nm. Small samples of Nd:YAG and ED‐2 glass were end pumped with a chopped cw 514.5‐nm argon‐ion laser in an identical geometrical arrangement. The stimulated emission cross section obtained for Nd:YAG at 1064 nm was found to be 7.6 ×10−19 cm.

Fluorescence determination of atmospheric NO2

The concentrations of nitrogen dioxide (NO2) in the atmosphere have been determined in real time and with a sensitivity of one part per billion. Laser excitation of NO2 was at 4416 and 4880 Å and fluorescence was monitored at 0.7 to 0.8 μm. Results obtained on typical smoggy days in Los Angeles are presented.

Lifetimes of the 4F3/2 state in Nd : YVO4

The fluorescence lifetime of the 4F3/2 state of Nd3+ in YVO4 crystals has been determined as a function of temperature and concentration. Over the temperature range 90–300 °K the lifetime is approximately 100 μsec and decreases to 87 μsec at 453 °K. The lifetime at 300 °K is found to depend on the Nd3+ concentration decreasing from 100 μsec at 0.4 at.% to 60 μsec at 1.6 at.%.

Atmospheric NO 2 determination by 442-nm laser induced fluorescence

An atmospheric monitor with a detectability of 0.6 ppbv, utilizing a compact He-Cd laser at 442 nm for excitation of the NO(2) molecules is described. Photon-counting techniques were employed to detect the NO(2) fluorescence transmitted through a bandpass liquid solution filter that did not fluoresce upon absorption of scattered laser light. Operational characteristics of the instrument are described. Results obtained in ambient air monitoring are presented.

Laser chemical etching of vias in GaAs

Rapid drilling of vias in thick wafers (381 µm) of GaAs has been achieved by a laser assisted etching process. The technique utilized a cw visible argon ion laser and an etchant gas of low pressure Cl2. Data on the dependence of the etch rate on the laser power, wavelength, and Cl2gas pressure are presented.

Stimulated emission cross sections of Nd:YVO4 and Nd:La2Be2O5 (BeL)

The stimulated emission cross sections σ of the 4F3/2→4I11/2 transitions have been measured for a‐axis Nd:YVO4 (1064.1 nm, σ = 19.0×10−19 cm2), x‐axis Nd:BeL (1079.2 nm, σ = 1.54×10−19 cm2), and y‐axis Nd:BeL (1070.1 nm, σ = 2.31×10−19 cm2).

New Nd:YAG laser transitions 4 F 3/2 → 4 I 9/2

Oscillation at 0.939, 0.900, 0.891 μm was obtained by end pumping a Nd:YAG rod at room temperature with the output of a pulsed xenon ion laser.

cw room‐temperature laser operation of Nd : CAMGAR at 0.941 and 1.059 μ

Continuous‐wave laser operation at 300 °K at 941 and 1059 nm has beeen demonstrated using Nd : CAMGAR. Discrimination against the 1059‐nm line required only tuned dielectric mirrors because of the strong 941‐nm fluorescence. Gain and loss coefficients at 1059 nm were determined.