Optical source model for the 23.2–23.6 nm radiation from the multielement germanium soft X-ray laser

• Published in: Optics communications 1999-10, Vol.169 (1), p.123-133
• Main Authors: Burge, R.E., Yuan, X.-C., Slark, G.E., Browne, M.T., Charalambous, P., Lewis, C.L.S., Cairns, G.F., MacPhee, A.G., Neely, D.
• Format: Article
• Language: English
• Subjects: Coherence; Emission, absorption, and scattering of x and γ radiation; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Lasers; Optics; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Plasma properties; Source size; X- and γ-ray lasers; XUV laser
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/S0030-4018(99)00394-6

Distributions of source intensity in two dimensions (designated the source model), averaged over a single laser pulse, based on experimental measurements of spatial coherence, are considered for radiation from the unresolved 23.2/23.6 nm spectral lines from the germanium collisional X-ray laser.The model derives from measurements of the visibility of Young slit interference fringes determined by a method based on the Wiener–Khinchin theorem. Output from amplifiers comprising three and four target elements have similar coherence properties in directions within the horizontal plane corresponding to strong plasma refraction effects and fitting the coherence data shows source dimensions (FWHM) are ∼26 μm (horizontal), significantly smaller than expected by direct imaging, and ∼125 μm (vertical: equivalent to the height of the driver excitation).