Black phosphorus(BP), with thickness-dependent direct energy bandgaps(0.3–2 eV), shows an enhanced nonlinear optical response at near-and mid-infrared wavelengths. In this paper, we present experimentally multilayer ...Black phosphorus(BP), with thickness-dependent direct energy bandgaps(0.3–2 eV), shows an enhanced nonlinear optical response at near-and mid-infrared wavelengths. In this paper, we present experimentally multilayer BP flakes coated on microfiber(BCM) as a saturable absorber with a modulation depth of 16% and a saturable intensity of 6.8 MW∕cm^2. After inserting BCM into an Er-doped fiber ring laser, a stable dual-wavelength Q-switched state with central wavelengths of 1542.4 nm and 1543.2 nm(with wavelength spacing as small as 0.8 nm) is obtained with the aid of two cascaded fiber Bragg gratings as a coarse wavelength selector.Moreover, single-wavelength Q-switched operation at 1542.4 nm or 1543.2 nm is also realized, which can be switched between the two wavelengths flexibly just by adjusting the intracavity birefringence. These results suggest that BP combined with the cascaded fiber gratings can provide a simple and feasible candidate for a multiwavelength fiber laser. Our fiber laser may have potential applications in terahertz generation, laser radar,and so on.展开更多
基金National Natural Science Foundation of China(NSFC)(61490710,61505122,61775142)Science and Technology Planning Project of Guangdong Province(2016B050501005)+1 种基金Specialized Research Fund for the Shenzhen Strategic Emerging Industries Development(JCYJ20170412105812811)Natural Science Foundation of SZU(2017018)
文摘Black phosphorus(BP), with thickness-dependent direct energy bandgaps(0.3–2 eV), shows an enhanced nonlinear optical response at near-and mid-infrared wavelengths. In this paper, we present experimentally multilayer BP flakes coated on microfiber(BCM) as a saturable absorber with a modulation depth of 16% and a saturable intensity of 6.8 MW∕cm^2. After inserting BCM into an Er-doped fiber ring laser, a stable dual-wavelength Q-switched state with central wavelengths of 1542.4 nm and 1543.2 nm(with wavelength spacing as small as 0.8 nm) is obtained with the aid of two cascaded fiber Bragg gratings as a coarse wavelength selector.Moreover, single-wavelength Q-switched operation at 1542.4 nm or 1543.2 nm is also realized, which can be switched between the two wavelengths flexibly just by adjusting the intracavity birefringence. These results suggest that BP combined with the cascaded fiber gratings can provide a simple and feasible candidate for a multiwavelength fiber laser. Our fiber laser may have potential applications in terahertz generation, laser radar,and so on.
