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DOE OSTI · 2234022

Selective Detection in Impulsive Low-Frequency Raman Imaging Using Shaped Probe Pulses

Shivkumar, Siddarth·Ranann, Dekel·Metais, Samuel·Suresh, Sisira·Forget, Nicolas·Bartels, Randy·Oron, Dan·Rigneault, Hervé
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Abstract

Impulsive stimulated Raman scattering (ISRS) using a single short femtosecond pump pulse to excite molecular vibrations offers an elegant pump-probe approach to perform vibrational imaging below 200 cm –1 . One shortcoming of ISRS is its inability to offer vibrational selectivity as all the vibrational bonds whose frequencies lie within the short pump-pulse bandwidth are excited. To date, several coherent control techniques have been explored to address this issue and selectively excite a specific molecular vibration by shaping the pump pulse. There has not been any systematic work that reports an analogous shaping of the probe pulse to implement preferential detection. In this work, we focus on vibrational imaging and report vibrational selective detection by shaping the probe pulse in time. Here, we demonstrate numerically and experimentally two pulse-shaping strategies with one functioning as a vibrational notch filter and the other functioning as a vibrational low-pass filter. This enables fast (25 μs/pixel) and selective hyperspectral imaging in the low-frequency regime (< 200 cm –1 ).

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74 ATOMIC AND MOLECULAR PHYSICSanalytical chemistrybiomoleculescoherent Raman scatteringimpulsive stimulated Raman scatteringmolecular spectraoptical transient phenomenapulse shapingstimulated Ramantime-resolved light scattering spectroscopyultrafast femtosecond pump probe

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Shivkumar, Siddarth, Ranann, Dekel, Metais, Samuel, Suresh, Sisira, Forget, Nicolas, Bartels, Randy, Oron, Dan, Rigneault, Hervé. 2023-05-23. Selective Detection in Impulsive Low-Frequency Raman Imaging Using Shaped Probe Pulses. https://doi.org/10.1103/physrevapplied.19.054075

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