Na, Dongsoo Park, Kichul Park, Ki-Hwan Song, Yong-Won 2024-01-20T00:02:56Z 2024-01-20T00:02:56Z 2021-09-03 2017-11-24 0957-4484 https://pubs.kist.re.kr/handle/201004/122043 Black phosphorus (BP) has attracted increasing attention due to its unique electrical properties. In addition, the outstanding optical nonlinearity of BP has been demonstrated in various ways. Its functionality as a saturable absorber, in particular, has been validated in demonstrations of passive mode-locked lasers. However, normally, the performance of BP is degraded eventually by both thermal and chemical damage in ambient conditions. The passivation of BP is the critical issue to guarantee a stable performance of the optical devices. We quantitatively characterized the mode-locked lasers operated by BP saturable absorbers with diversified passivation materials such as polydimethylsiloxane (PDMS) or Al2O3, considering the atomic structure of the materials, and therefore the hydro-permeability of the passivation layers. Unlike the BP layers without passivation, we demonstrated that the Al2O3-passivated BP layer was protected from the surface oxidation reaction in the long-term, and the PDMS-passivated one had a short-term blocking effect. The quantitative analysis showed that the time-dependent characteristics of the pulsed laser without passivation were changed with respect to the pulse duration, spectral width, and time-bandwidth product displaying 550 fs, 2.8 nm, and 0.406, respectively. With passivation, the changes were limited to <43 fs, <0.3 nm, and <0.012, respectively. English IOP PUBLISHING LTD EVANESCENT FIELD INTERACTION ATOMIC LAYER DEPOSITION CARBON NANOTUBE GRAPHENE TRANSISTORS Passivation of black phosphorus saturable absorbers for reliable pulse formation of fiber lasers Article 10.1088/1361-6528/aa9429 1 NANOTECHNOLOGY, v.28, no.47 NANOTECHNOLOGY 28 47 scie scopus 000414414800001 2-s2.0-85033669268 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Science & Technology - Other Topics Materials Science Physics Article EVANESCENT FIELD INTERACTION ATOMIC LAYER DEPOSITION CARBON NANOTUBE GRAPHENE TRANSISTORS black phosphorus saturable absorber ultrafast pulse laser polydimethylsiloxane passivation alumina passivation