Spectral modulation of third-harmonic generation by molecular alignment and preformed plasma
Min Li(李敏)1, An-Yuan Li(李安原)1, Bo-Qu He(何泊衢)2, Shuai Yuan(袁帅)1, He-Ping Zeng(曾和平)1,2
1 Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System(Ministry of Education), School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China;
2 State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
We demonstrate spectral modulation of third-harmonic generation from molecular alignment effects. The third harmonic spectrum is broadened or narrowed under different influences of cross-phase modulations originating from various molecular alignment revivals. Furthermore, the spectrum and spatial distribution of the generated third harmonic pulse change dramatically in the presence of a preformed plasma. Under the influence of a preformed plasma, a narrower third harmonic spectrum is observed, and the conical third-harmonic pulse increases while the axial part decreases. The investigation provides an effective method to modulate the spectral characteristic and spatial distribution of third-harmonic generation from intense femtosecond filament.
(Ultrafast processes; optical pulse generation and pulse compression)
Fund:
Project supported by the National Key Scientific Instrument Project, China (Grant No. 2012YQ150092), the National Basic Research Program of China (Grant No. 2011CB808105), the National Natural Science Foundation of China (Grant No. 11434005), China Postdoctoral Science Foundation (Grant No. 2014M560348), the National Natural Science Foundation of China (Grant No. 11504237), and the Shanghai Municipal Science and Technology Commission, China (Grant No. 14JC1401600).
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