High power broadband continuum source based on an all-PM-fiber master oscillator nonlinear power amplifier

摘要

In an allpolarizationmaintainingfiber master oscillator power amplifier system at 1064 nm under all normal dispersion, intense nanosecond emission was generated with spectral broadening from 980 to 1600 nm. In such a fiber nonlinear power amplifier, efficient power scaling is able to be free from significant depletion because both laser amplification and nonlinear conversion are simultaneously employed. As a result, output peak power up to 117 kW with a pulse energy of 1.2 mJ is generated with a maximum core intensity of 30 GW cm~(-2). In addition, the conversion efficiency is 66% for a pulse duration of 6.1 ns at the moderate repetition of 20 kHz. The output level is close to the damage threshold for long-term operation. The onset and interplay of constituted fiber nonlinearities can be addressed, especially from single mode to a few modes, stage by stage. Furthermore, the seeding influence on the spectral broadening reveals its versatility for enabling many potential applications. For seeding by a highly controlled diode laser at the nanojoule level, a double-pass preamplifier significantly improves the energy extraction, resulting in a high input level for an efficient nonlinear power amplifier. Such a linearly polarized light source composed of an intense 1064 nm pump and a broad sideband seed is beneficial for efficiently driving broadband tunable optical parametric amplification.