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摘要
Ultrafast hemispherical angle-resolved light scattering technique is applied to monitor the insulator-to-metal phase transition of highly oriented VO2 crystalline films, where transition is induced by femtosecond laser pulses. This approach reveals principal differences in transient dynamics of multi-scale VO2 grains for thermally and light-induced phase transformation, showing anisotropic and grain-size-dependent behavior with high resolution in space and time. Complete photoinduced transition occurs within 500 fs. However, VO2 grains of different sizes show different transition rates. The highest rate is found for clusters with lower concentration of structural defects and deformations. The twinning process in VO2 film is considerable for the thermally induced transition but is not detected for the ultrafast light-induced one.
- 出版日期2013-10-21
