文摘
A solvothermal method for fabricating ultrasmall black phosphorus quantum dots (BPQDs) with uniform morphology as an optical saturable absorber is described by H. Zhang, X.-F. Yu, and co-workers on page 1223. Verified by femtosecond laser measurement, BPQDs are found to exhibit an excellent nonlinear optical response with a modulation depth higher than 30% and a saturable intensity at the level of GW cm−2.