Demonstration of soft X-ray laser generated in highly saturated capillary discharge amplifier with 4.0 mm and 3.2 mm inner diameter alumina capillaries

Capillary discharge highly saturated Ne-like Ar 46.9 nm laser had been firstly demonstrated with a 4.0 mm inner diameter alumina capillary. The intensity of laser is greater for the 4.0 mm inner diameter capillary than for the conventional 3.2 mm inner diameter capillary. The gain coefficients have been enhanced to 0.86 cm^-1 and 1.3^-1, for the 4.0 mm and 3.2 mm inner diameter alumina capillaries, respectively. Furthermore, an alumina capillary with a 4.0 mm or larger inner diameter possesses crucial advantages to achieve more intense or shorter wavelength soft X-ray laser.