In Search of Rationality in Human Longevity and Immortality.

The human body is machine-like, but self-moving, self-regulating, and self-adjusting, governed by willpower and intelligence. Aging of the body is basically a maintenance problem and so it could perhaps be postponed by thorough and frequent maintenance. Aging brings on a cascade of ills and health problems leading to deterioration of physical, mental, emotional, and social dimensions of life.

Efficient Generation of 200-230-nm Radiation in Beta Barium Borate by Noncollinear Sum-Frequency Mixing.

Tunable ultraviolet radiation in the 200-230-nm region has been generated with beta barium borate crystals by type I sum-frequency mixing of the second harmonic with the fundamental beam from a dye laser pumped by the second harmonic of the same Nd:YAG laser. A noncollinear phase-matching configuration has made it possible to realize conversion efficiency of 21% at 208.3 nm with input power densities as low as 28 MW/cm(2) for the fundamental and 2.

Generation of tunable 187.9-196-nm radiation in beta-Ba(2)BO(4).

Tunable 187.9-196-nm vacuum-ultraviolet radiation was generated at room temperature in a beta barium borate crystal by sum-frequency mixing of Nd:YAG laser radiation and the second harmonic of a dye laser pumped by the second harmonic of the same Nd:YAG laser. By use of the advantageous noncollinear phase-matching configuration, a peak power of 1.

Generation of tunable 187.9-196-nm radiation in beta-BaB(2)O(4): errata.

In Ref. 1, the first full sentence in the right-hand column of p. 1608 should read as: 'Although BBO is phase matchable down to 187 nm and shorter in this configuration without a very large (2-4 degrees ) change in theta (and hence in d(eff)), and B2 is also suitable to accommodate the phase matching, tunability below 187.

Multipass configuration to achieve high-frequency conversion in Li2B4O7 crystals.

A multipass configuration for second-harmonic generation of Nd:YAG laser radiation is demonstrated to produce, for the first time to the authors' knowledge in twin lithium tetraborate crystals, as much as 21% conversion efficiency even though the effective nonlinear coefficient of the crystal is as low as 1/6th that of KDP. Apart from crystals that have large walk-off angles, low effective nonlinear coefficients, or both, the simple experimental setup would also be quite suitable for those crystals, especially infrared crystals, that have large effective nonlinear coefficients but low laser damage thresholds.