Infrared—Ultraviolet Sum-Frequency Generation Spectrometer with a Wide Tunability of the Ultraviolet Probe

Abstract

We have constructed a multiplex infrared-ultraviolet (IR-UV) sum-frequency generation (SFG) spectrometer that has a wide tunable range (235-390 nm) of the UV probe wavelength. The tunable UV probe was obtained by doubling the signal output of an optical parametric amplifier pumped by a 400 nm picosecond pulse. A prism monochromator was used as a tunable sharp-cut bandpass filter to reduce stray light due to the scattering of the UV probe so that any wavelength within the tunable range can be chosen as that of the UV probe. The SFG spectra of p-mercaptobenzoic acid on a gold substrate was measured with 289 and 334 nm UV probes. The SFG vibrational band intensities due to the carbonyl stretch mode and a phenyl ring stretch mode measured with the 289 nm probe were approximately three times larger than those measured with the 334 nm probe. The enhancement was ascribed to an electronic resonant effect.

Identification of chemical species of fluorescein isothiocyanate isomer–I (FITC) monolayers on platinum by doubly resonant sum‐frequency generation spectroscopy

“…The details of the spectrometer have been published elsewhere. 11,14,15 In short, the probe light source was based on a Ti : sapphire amplifier (TITAN II, Quantronix) operated at 1 kHz. The amplifier produced an 800-nm fundamental output of 2.4 mJ pulse energy and 110 fs time duration.…”

“…7,8 DR-SFG spectroscopy has been applied to a number of systems such as a spin-coated dye film on silica, 8 C 60 monolayer on silver, 9 and a colored protein monolayer on platinum 10 with visible probes, and a benzene derivative on gold with UV probes. 11 DR-SFG also allows detection of chirality of thin films. 12,13 There are several advantages of DR-SFG.…”

Molecular Orientations and Conformations of Air/Fluoroalkyl Acrylate Polymer Interfaces Studied by Heterodyne-Detected Vibrational Sum Frequency Generation

“…The reflected LO and the SFG from the sample in reflection passed through a Glan−Thompson prism made of calcite to select their polarization. They were introduced into a polychromator (TRIAX550, HORIBA Jovin Yvon, focal length: 550 mm, grating: 1200 grooves/mm) after a prism monochromator (CT25-UV, JASCO) 33 and interfered with each other in the frequency domain. The interference fringe pattern was finally detected with a liquid nitrogen-cooled CCD detector (LN/CCD-1340/400-EB/1, Roper Scientific).…”

Novel SiO2-Deposited CaF2 Substrate for Vibrational Sum-Frequency Generation (SFG) Measurements of Chemisorbed Monolayers in an Aqueous Environment

“…The vibrational SFG spectrometer employed a multichannel detection scheme with the narrow bandwidth Vis probe and the broad bandwidth IR probe pulses. 46,47 The probe light sources were based on an amplified Ti:Sapphire laser (3.5 mJ, 1 kHz, Legend Elite, Coherent). The femtosecond broadband IR (∼240 cm −1 FWHM at 2900 cm −1 , ∼170 cm −1 FWHM at 1600 cm −1 ) and picosecond narrow-band Vis pulses (∼8 cm −1 FWHM) were generated by using femtosecond and picosecond OPAs (TOPAS, Light Conversion), respectively.…”