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The use of the Phillips–Tikhonov regularization is proposed for numerically stabilizing the ill-conditioned plasma image reconstructions. An objective function to be minimized leads to a linear estimator of the image intensity distribution and, with the aid of the singular value decomposition, makes it possible to use the generalized cross validation for optimizing a regularization parameter. An excellent behavior of the estimator with computational facility is obtained on the Hα emission computerized tomography of a toroidal plasma.

We report a compact diode-laser pumped Nd:GdVO(4) laser with stable dual-wavelength output at 1063 nm and 1065 nm simultaneously. Two types of resonant cavity configurations were presented to support the stable dual-wavelength operation of the laser. Using a polarization beam splitter(PBS) included T-shaped cavity, we obtained a total power output over 5 W in two orthogonal polarized beam directions with 4 W in sigma polarization (1065.5 nm) and 1 W in pi polarization (1063.1 nm). By combining a half-wave-plate with the PBS in the laser cavity, a new configuration favoring one beam direction dual-wavelength output with same polarization direction was realized. A phenomenon of further line splitting was observed in both 1065 nm and 1063 nm.

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