SPATIAL COHERENCE OF SHORT-WAVELENGTH HIGH-ORDER HARMONICS

Nonperturbative high-order harmonic conversion of high-intensity, ultr afast laser pulses in gases represents a unique means to generate high -brightness, coherent XUV, and soft X-ray radiation. We review the phy sics controlling the spatial qualities of harmonic radiation and recen t experimental measurements of high-order harmonic spatial profiles. W e also examine the factors controlling the spatial coherence of the ha rmonics. A detailed series of Young's two-slit experiments that measur e the spatial coherence of the harmonics is presented. These measureme nts indicate that the harmonics exhibit good fringe visibility and hig h spatial coherence.