Multi-photon excitation in ZnO material by femtosecond pulses

Multi-photon excitation in ZnO material by femtosecond (fs) laser pulses around 800 nm was clearly observed. Under the intense field generated by fs pulses, two-photon absorption process was found very efficient in the excitation of the band edge emission from ZnO material under detuning condition. Nonlinear optical effects, such as Stark effect and Rabi effect, that may emerge under intense field are suggested to be responsible for this efficient excitation via two-photon absorption process. We consider that this NLO route to generate photoluminescence in ZnO material is meaningful in the research of blue-violet semiconductor laser field. Keywords: ZnO; nanowire; multi-photon excitation.