Electronically resonant third-order sum frequency generation spectroscopy using a nanosecond white-light supercontinuum

Abstract

Third-order sum frequency generation (TSFG) is one of the third-order nonlinear optical processes, and has the generation mechanism analogous to third harmonic generation (THG). By using a white-light supercontinuum, we can obtain broadband multiplex TSFG spectra. In the present study, we developed an electronically resonant TSFG spectrometer, and applied it to obtain TSFG spectra of hemoproteins. Analyzed TSFG ratio spectra clearly showed the resonant enhancement attributable to the electronic state of hemoproteins. This is a promising method for the imaging of electronic states of molecules inside living cells or tissues.

Multimodal Imaging of Living Cells with Multiplex Coherent Anti-stokes Raman Scattering (CARS), Third-order Sum Frequency Generation (TSFG) and Two-photon Excitation Fluorescence (TPEF) Using a Nanosecond White-light Laser Source

“…The detailed signal generation mechanism has been already explained in our previous report. 30 In the present case, the refractive indices difference between the polystyrene beads and surrounding air provided the image contrast of TSFG. Since the bead diameter was 1 μm, it approximately corresponded to a point source for the multiphoton processes.…”

Multimodal and multiplex spectral imaging of rat cornea ex vivo using a white‐light laser source

“…This structure is assigned as the complex of basement membrane and Bowman's layer. Recently we have developed electronically resonant multiplex TSFG spectroscopy . It will thus be able to analyze electronic state of biomolecules inside cornea or other tissues ex vivo .…”

High-resolution infrared imaging of biological samples with third-order sum-frequency generation microscopy

“…The TSFG technique is based on an optical nonlinearity that has not been used before for imaging biological samples. Although electronically resonant and nonresonant versions of the TSFG interaction have been used as contrast mechanisms in NLO microscopy [32,33], a vibrationally sensitive variation of the technique constitutes a new approach to biological imaging. The MIR-based TSFG interaction is exclusively sensitive to IR-active vibrational modes [25], and thus offers a direct NLO analogue of MIR absorption microspectroscopy.…”