Single element material sulfur quantum dots nonlinear optics and ultrafast photonic applications

Abstract

Single element low dimensional nanomaterials have been widely used in many electronic and optoelectronic application owing to their strong photo-material interactions and saturable absorption characteristics. In this work, we studied the saturable absorption properties of sulfur quantum dots (SQDs). The SQDs show an excellent saturable absorption performance with a nonlinear absorption coefficient of −5.89 × 10-2 cm/GW and a figure of merit of −10.2 × 10−14 esu cm. Furthermore, we demonstrated the first SQDs saturable absorber (SA) as a mode locker in a mode-locking erbium-doped fiber laser for the generation of ultrafast laser pulses (720 fs) with a center wavelength of 1530.6 nm and a corresponding single pulse energy up to 0.972 nJ. The experimental results open a new avenue for the use of SQDs in laser and photon applications.