Black phosphorus flakes covered microfiber for Q-switched ytterbium-doped fiber laser.

We demonstrate a passively Q-switched ytterbium-doped fiber laser based on black phosphorus (BP) flakes covered microfiber. The BP saturable absorber is fabricated by sandwiching a microfiber between two pieces of polydimethylsiloxane supported BP flakes film, which is prepared by the mechanical exfoliation method. In this case the BP flakes can be well protected from the action of air and moisture.