Answers are grounded in this paper and cite their sources.
Phase-matched high-order-harmonic generation of Ti:sapphire laser pulses of ≈10¹⁴W/cm² has been demonstrated using a gas-filled hollow fiber. The high-order-harmonic spectrum emitted from the fiber showed an intensity distribution significantly different from that in free space, indicating more than a hundred times enhancement around the 25th harmonic. A simple phase-matching calculation considering positive dispersion due to plasma and negative dispersion due to neutrals indicates that macroscopic phase matching achieved in the fiber is responsible for the strong enhancement.
No takes yet. Share an insight, caveat, or question.
Tamaki et al. (1999) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: