Black phosphorus as a new broadband saturable absorber for infrared passively Q-switched fiber lasers

TL;DR

This paper demonstrates black phosphorus as a broadband saturable absorber capable of generating Q-switched pulses at multiple infrared wavelengths, showcasing its potential for fiber laser applications.

Contribution

It introduces black phosphorus as a novel two-dimensional material for broadband saturable absorption in fiber lasers, with experimental verification at multiple wavelengths.

Findings

Q-switched pulses at 1550 nm with 9.35-31 us width

Over 100 nm tunable wavelength range from 1832 to 1935 nm

First verification of BP's broadband saturable absorption property

Abstract

Black phosphorus (BP) with its enticing electric and optical properties is intensely researched in the field of optoelectronics. In this paper, Q-switched pulses at 1550 nm and 2 um wavelengths are obtained by inserting bulk-structured BP based saturable absorber (SA) into an erbium-doped fiber laser (EDFL) and an thulium/holmium-doped fiber laser (THDFL), respectively. The BP-SA was prepared by depositing powered BP material on to the flat side of a side-polished single mode fiber. Q-switched 1550 nm pulses with width tuned from 9.35 to 31 us were obtained for the EDFL. For the THDFL, over 100 nm wavelength range could be achieved from 1832 to 1935 nm by adjusting the pump power. To the best of our knowledge, these results demonstrated the broadband saturable absorption property of BP and for the first time verified that BP as a new two-dimensional material for applications in saturable absorption devices.