Two-dimensional transition metal dichalcogenides are considered promising materials for next-generation photonics and nano-optical devices. Although many previous reports have shown saturable absorption of molybdenum ...Two-dimensional transition metal dichalcogenides are considered promising materials for next-generation photonics and nano-optical devices. Although many previous reports have shown saturable absorption of molybdenum diselenide(Mo Se2), these nonlinear optical(NLO) properties of Mo Se2 were measured in separate works and under different conditions with their hot-carrier relaxations. Here, we conducted a series of coherent studies on the NLO properties of few-layer Mo Se2 via open-aperture Z-scan and degenerate pump-probe techniques. These measurements were taken to test the materials' capabilities as a slow-saturable absorber. A slowabsorber model was employed to analyze the NLO measurements, and the results show that the NLO modulation depth was modeled to be 7.4% and 15.1% for the linear absorption coefficients of 5.22 cm-1 and 6.51 cm-1,respectively. The corresponding saturated intensities were modeled to be 39.37 MW∕cm2 and 234.75 MW∕cm2,respectively. The excitation carrier recovery time of few-layer Mo Se2 was measured by degenerate pump-probe techniques to be ～220 ps. These nonlinear optical performances make it a promising slow-saturable absorber for passive mode locking in femtosecond lasers.展开更多
基金Science Foundation Ireland(SFI)(12/IA/1306)Seventh Framework Programme(FP7)(ISLA project no.287732)+4 种基金National Natural Science Foundation of China(NSFC)(61522510,61675217,11704261,11575118)Strategic Priority Research Program of Chinese Academy of Sciences(CAS)(XDB16030700)Key Research Program of Frontier Science of Chinese Academy of Sciences(QYZDBSSW-JSC041)the Program of Shanghai Academic Research Leader(17XD1403900)Shenzhen Key Lab Fund(ZDSYS20170228105421966)
文摘Two-dimensional transition metal dichalcogenides are considered promising materials for next-generation photonics and nano-optical devices. Although many previous reports have shown saturable absorption of molybdenum diselenide(Mo Se2), these nonlinear optical(NLO) properties of Mo Se2 were measured in separate works and under different conditions with their hot-carrier relaxations. Here, we conducted a series of coherent studies on the NLO properties of few-layer Mo Se2 via open-aperture Z-scan and degenerate pump-probe techniques. These measurements were taken to test the materials' capabilities as a slow-saturable absorber. A slowabsorber model was employed to analyze the NLO measurements, and the results show that the NLO modulation depth was modeled to be 7.4% and 15.1% for the linear absorption coefficients of 5.22 cm-1 and 6.51 cm-1,respectively. The corresponding saturated intensities were modeled to be 39.37 MW∕cm2 and 234.75 MW∕cm2,respectively. The excitation carrier recovery time of few-layer Mo Se2 was measured by degenerate pump-probe techniques to be ～220 ps. These nonlinear optical performances make it a promising slow-saturable absorber for passive mode locking in femtosecond lasers.
