作者：Xiaolin Lu
關鍵字：SFG, biological interfaces
論文來源：會議
具體來源：OSA Publishing > Conference Papers > PIBM > 2017>T2C > Page T2C.1
發表時間：2017年
The nonlinear spectroscopy - Sum frequency generation (SFG) vibrational spectroscopy can be viewed as a collective wisdom or/and inevitable outcome of nonlinear optics and vibrational spectroscopy. The work done by Shen et al. paved the theoretical and experimental foundation for the SFG fields nowadays. The first series of papers using SFG were published in 1987 by Shen, et al. on studying organic molecules at interfaces. To date, introduction of the SFG theory (including nonlinear optics) can be found in a large number of literatures, which facilitate understanding of a SFG process at surfaces and interfaces. A frequency-fixed visible beam and a frequency-tunable infrared beam temporally and spatially overlap at a surface or interface, where the inversion symmetry of the molecular distribution is broken. A third sum frequency beam with its frequency being the sum of the visible and infrared frequencies, is generated from molecules at the surface or interface and its intensity can be measured by a detector (monochromator /photo-multiplier tube (PMT)). When the IR frequency is tuned across a vibrational excitation frequency range of the surface/interfacial molecules. The intensity of the SF beam is resonantly enhanced and an SFG spectrum can be acquired by plotting the intensity of the SF beam as a function of the IR frequency. By analyzing SFG spectra, the molecular information can be acquired.
https://www.osapublishing.org/abstract.cfm?uri=PIBM-2017-T2C.1