Using a model of high-harmonic generation that couples a fully quantum calculation with a semi-classical electron trajectory picture, we show that a new type of phase matching is possible when an atom is driven by an optimal ...

We demonstrate the use of a deformable-mirror pulse shaper, combined with an evolutionary optimization algorithm, to correct high-order residual phase aberrations in a 1-mJ, 1-kHz, 15-fs laser amplifier. Frequency resolved ...

Forests are aesthetically challenging because of a perennial, dynamic sense of deep time, experiencing an archetype of creation. Scientific appreciation of natural history is necessary though not sufficient for an intense, ...

We demonstrate a simple and practical single-stage ultrafast laser amplifier system that operates at a repetition frequency from 1 to 10 kHz, with millijoule pulse energy and as much as 13 W of average power. The repetition ...

Report on trip to Nepal, environmental conservation, and human development, 1998. A trek in the Himalayas proves a stimulating mix of the sublime majesty of nature and the simple life of the Nepalis. They eke out a living, ...

Simultaneously recorded discrete excitations of Earth-ionosphere cavity resonances at Silberborn, Germany, and Hollister, California, ~9.1 Mm apart, are used to triangulate source locations of lightning flashes in the ...

Environmental ethics is an invitation to moral development. Respect for human life is only a subset of respect for all life. What ethics is about is seeing outside your own sector of self-interest, of class interest. A ...