Abstract

High harmonic generation (HHG) is an excellent source of extreme ultraviolet (EUV) radiation that upconverts an intense laser pulse to much shorter wavelengths. Over the past decade, many experiments have studied this process, providing detailed insights into the physics of HHG. Phase matching the HHG process, either using a hollow waveguide,(1) or using a near-plane-wave geometry, (2, 3) increases the brightness of the source by orders of magnitude and generates and EUV beam with full spatial coherence.(4) In this work, we experimentally demonstrate that phase-matching of HHG radiation can be extended to shorter wavelengths and higher pulse energies using a structured hollow waveguide. Moreover, this photonic structure results in the generation of a broad continuum that may support an isolated 250 attosecond EUV pulse, as has been previously predicted theoretically.(5) This work is a compelling demonstration of the applicability of photonics technology concepts to a new region of the spectrum.

© 2002 Optical Society of America