Sub-second hyper-spectral low-frequency vibrational imaging via impulsive Raman excitation

Hervé Rigneault (1) , Dekel Raanan (2) , Xavier Audier (3, 1) , Siddarth Shivkumar (3, 1) , Maor Asher (2) , Matan Menahem (2) , Omer Yaffe (2) , Nicolas Forget (4) , Herve Rigneault (3, 1) , Dan Oron (5, 2)

1 MOSAIC - MOSAIC
2 Weizmann Institute of Science [Rehovot, Israël]
3 FRESNEL - Institut FRESNEL
4 FASTLITE
5 Department of Physics of Complex Systems

Real time vibrational microscopy has been recently demonstrated by various techniques, most of them utilizing the well-known schemes of coherent anti-stokes Raman scattering (CARS) and stimulated Raman scattering (SRS). These techniques readily provide valuable chemical information mostly in the higher vibra-tional frequency regime (> 400 cm −1). Addressing the low vibrational frequency regime (< 200 cm −1) is challenging due to the usage of spectral filters that are required to isolate the signal from the Rayleigh scattered excitation field. In this letter we report on rapid, high resolution, low-frequency (< 130 cm −1) vibrational mi-croscopy using impulsive coherent Raman excitation. By combining impulsive excitation with a fast acousto-optics delay line we detect the Raman-induced optical Kerr lensing and spectral shift effects with a 25µs pixel dwell time to produce shot-noise limited low frequency hyper-spectral images of various samples.

Domaines: Optique / photonique

Hervé Rigneault, Dekel Raanan, Xavier Audier, Siddarth Shivkumar, Maor Asher, et al.. Sub-second hyper-spectral low-frequency vibrational imaging via impulsive Raman excitation. Optics Letters, 2019, 44 (21), pp.5153. ⟨10.1364/OL.44.005153⟩. ⟨hal-02320742⟩