Supporting Information
An Approach to Compatible Multiple Nonlinear Vibrational Spectroscopy Measurements Using Commercial Sum Frequency Generation System
Shuji Ye,* Feng Wei Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui, P.R.China 230026
The IR spectra of riboflavin FTIR spectra were obtained using a Nicolet 8700 spectrometer. Spectra collected were averages of 32 scans at a 1 cm-1 resolution.
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Figure S1. The IR spectra of Riboflavin
The SFG and IIV-TPF-FWM spectra of lumichrome
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Figure S2. The SFG (ssp) and IIV-TPF-FWM (sspp) spectra of lumichrome The feasibility to collect DFG spectra using this compatible system Similar to SFG, DFG is also based on a coherent second-order nonlinear process. The level schemes of the vibrational and electronic configurations involved in DFG process are shown in Figure S3. According to energy and momentum conservation,1-3 DFG have the following relationships: ω = ω − ω DFG vis IR (S1)
k DFG = k vis − k IR (S2)
In the case with an IR beam at 3000 cm-1, DFG will emerge at the angle of 65.31°and the wavelength of 633.17 nm (see Figure S4). The emerging angle is close to the emerging angle of SFG (61.44°) and IIV-TPF-FWM (60.3°). Therefore DFG labview software can be modifiedby controlling the monochromator at ωDFG (ωDFG =ωvis-ωIR) when scanning the IR frequency (ωIR). DFG spectra of riboflavin are given in Figure S5. Similar to SFG, all of the eight polarization combinations have non-vanishing signals. Accepted that the spectra intensity is different, DFG and SFG show the same peak positions. The intensity of DFG spectra is about 5-10% of the intensity of SFG spectra.
Figure S3. Level schemes of the Figure S3. Sketch of the visible and infrared laser beams vibrational and electronic used to generate the SFG, DFG and FWM signals on the configurations involved in DFG. samples.
2500 2000 DFG 1500 ssp 1000 500 2500 ppp 2000 1500 1000 500 2500 2000 psp 1500 1000 500 3500 Normallized DFG Intensity 3000 spp 2500 2000 1500 1000 500 0 1100 1200 1300 1400 1500 1600 1700 1800 Wavenumber (cm-1)
Figure S5. The DFG spectra of (-)-riboflavin. Reference 1. Y. R.Shen, The Principles of Nonlinear Optics; John Wiley& Sons: New York, 1984. 2. B.Bozzini, A.Bund, B.Busson, C.Humbert, A.Ispas, C.Mele, A.Tadjeddine, Electrochem. Commun., 2010, 12, 56–60. 3. A.Tadjeddine, A.Le Rille, O.Pluchery, F.Vidal, W.Q.Zheng, A.Peremans, Phys.Stat.Sol. A,
1999, 175, 89-107.