Solitary beam propagation in periodic layered Kerr media enables high-efficiency pulse compression and mode self-cleaning

摘要

a Illustration of the repetitive self-focusing and diverging pattern in PLKM, which is equivalent to a space-time coupled nonlinear optical resonator. The space-time coupled propagation of femtosecond pulses for the solitary modes and in the dissipative region is presented. When the propagation is in the dissipative region, strong conical emission is contributed by the optical energy at the temporal centre of the pulse, leading to temporal pulse splitting. b Universal relationship of the normalized beam radius squared, i.e., w2/λL, as a function of the nonlinear phase b for the resonator solitary modes (solid blue line). The dashed lines represent the boundaries for Pthr < P < 2Pthr. The symbols are the experimental results under different resonator lengths. The yellow shaded area is the “quasi-stable oscillatory region”. Inset: Variation in the far-field beam radius as a function of the applied nonlinear phase and incident pulse energy for L = 50.8 mm and bc = 1.2. c Experimentally measured beam radii through propagation in the PLKM with L = 50.8 mm and bc = 1.2 under the resonant condition. The beam radius in each layer is indicated by the star symbols. d Evolution of the temporal intensity profiles as the pulses propagate through the PLKM under the solitary mode (Ein = 260 μJ) and in the dissipative region (Ein = 450 μJ)