Phase-matching high-order harmonics in a semi-infinite gas cell geometry

The generation of intense attosecond pulses with a regular temporal structure depends critically on different quantum path contributions and their correlation by phase-matching the harmonic emission process. A number of geometries are available for the high-harmonic generation process in gases, with advantages like the precise tailoring of phase-matching conditions (cell-geometries) and disadvantages like low yields at increased repetition rates (jet-geometries). For applications in attosecond physics the most reliable solution has to be found. To this end we have investigated systematically the semi-infinite gas cell geometry which has been used for harmonic generation in recent years [1–2].