A novel SiO<sub>2</sub>-deposited CaF<sub>2</sub> (SiO<sub>2</sub>/CaF<sub>2</sub>) substrate for measuring vibrational sum-frequency generation (SFG) spectra of silane-based chemisorbed monolayers in aqueous media has been developed. The substrate is suitable for silanization and transparent over a broad range of the infrared (IR) probe. The present work demonstrates the practical application of the SiO<sub>2</sub>/CaF<sub>2</sub> substrate and, to our knowledge, the first SFG spectrum at the solid/water interface of a silanized monolayer observed over the IR fingerprint region (1780-1400 cm<sup>−1</sup>) using a back-side probing geometry. This new substrate can be very useful for SFG studies of various chemisorbed organic molecules, particularly biological compounds, in aqueous environments.
Vol. 7, Iss. 8 Virtual Journal for Biomedical Optics
ADCHARA PADERMSHOKE, SHOUTA KONISHI, MASATO ARA, HIROKAZU TADA, and TAKA-AKI ISHIBASHI, "Novel SiO2-Deposited CaF2 Substrate for Vibrational Sum-Frequency Generation (SFG) Measurements of Chemisorbed Monolayers in an Aqueous Environment," Appl. Spectrosc. 66, 711-718 (2012)