Sub-cycle pulse reportedly amplified beyond 50 mJ while retaining 1.4-octave bandwidth

Combining over fifty millijoules with 1.4-octave bandwidth

RIKEN's team reports developing an amplification approach for a sub-cycle laser pulse—a pulse that ends before its light field completes one oscillation. The reported pulse had an energy above 50 mJ, a 1.4-octave bandwidth, and a measured width of 6.7 femtoseconds, corresponding to 0.88 cycles at its stated central wavelength. The team also reported generating attosecond pulses using the amplified light.

The supplied account compares the result with previously reported sub-cycle laser pulse energies, but does not provide a directly comparable prior energy value.

RIKEN says it combined a waveform-synthesis seed-generation method with HNC-DCOPA amplification to produce a sub-cycle pulse above 50 mJ while maintaining a 1.4-octave bandwidth. It describes the energy as more than 100 times that of previously reported sub-cycle laser pulses.

High-energy sub-cycle pulses require both an exceptionally broad spectrum and amplification that preserves it. RIKEN says its result raises the reported pulse energy by more than 100-fold over earlier reported sub-cycle lasers. Higher-power half-cycle operation and zeptosecond-pulse applications remain simulation results or future development goals, not demonstrated outcomes.