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

TL;DR

This study demonstrates that copper capillaries can effectively guide high-intensity femtosecond laser pulses with high transmission efficiency, and investigates their reflectivity and lifetime under extreme conditions.

Contribution

It provides experimental evidence that copper capillaries can guide ultra-intense laser pulses up to 10^{19} W/cm^2, with detailed measurements of reflectivity and capillary lifetime.

Findings

70% transmission for 50 fs pulses at 10^{17} W/cm^2

Copper reflectivity remains high up to 10^{17} W/cm^2 in vacuum and helium

Capillary lifetime decreases with increasing pulse energy

Abstract

Propagation of high-intensity, high-contrast ($<10^{-8}$), 50\,fs laser pulses through triangilar copper capillaries is experimentally studied. The relative transmission through 20-mm-long, about 50\,$\mu$m wide capillaries is directly measured to be 70\% for input intensities up to $10^{17}\,\text{W/cm}^2$. The copper reflectivity in vacuum, helium, and air is measured in the intensity range of $10^{10}$--$10^{17}\,\text{W/cm}^2$. 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 up to $10^{19}\,\text{W/cm}^2$ on the capillary axis (that corresponds to $10^{17}\,\text{W/cm}^2$ 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.