Guiding femtosecond high-intensity high-contrast laser pulses by copper capillaries

Abstract

Propagation of high-intensity, high-contrast (<10−8), 50 fs laser pulses through triangular copper capillaries is experimentally studied. The relative transmission through 20-mm-long, about 50 μm wide capillaries is directly measured to be 70% for input intensities up to 1017 W/cm2. The copper reflectivity in vacuum, helium, and air is measured in the intensity range of 1010–1017 W/cm2. No reflectivity decrease in vacuum and helium is observed, which leads to the conclusion that copper capillary waveguides can efficiently guide laser pulses of intensities greater than 1019 W/cm2 on the capillary axis (that corresponds to 1017 W/cm2 on the walls). The reduction of the transmission efficiency to zero after a number of transmitted pulses is observed, which is caused by plug formation inside the capillary. The dependence of the capillary lifetime on the pulse energy is measured.