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Brillouin spectrometers, used for characterizing material mechanical properties, traditionally employ etalons such as Fabry-Pérot interferometers and virtually imaged phased arrays (VIPA) that use spatial dispersion of the spectrum for measurement. Here, we introduce what we believe to be a novel approach to Brillouin spectroscopy using hot atomic vapors. Using laser induced circular dichroism of the rubidium D2 line in a ladder-type configuration, we developed a narrow-band monochromator for Brillouin analysis. Unlike etalon-based spectrometers, atomic line monochromators operate in free-space, facilitating Brillouin spectroscopy integration with microscopy instruments. We report the transmission and spectral resolution performances of the spectrometer and demonstrate Brillouin spectra measurements in liquids.
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Spectral resolution enhancement for impulsive stimulated Brillouin spectroscopy by expanding pump beam geometry
Brillouin microscopy has recently emerged as a powerful tool for mechanical property measurements in biomedical sensing and imaging applications. Impulsive stimulated Brillouin scattering (ISBS) microscopy has been proposed for faster and more accurate measurements, which do not rely on stable narrow-band lasers and thermally-drifting etalon-based spectrometers. However, the spectral resolution of ISBS-based signal has not been significantly explored. In this report, the ISBS spectral profile has been investigated as a function of the pump beam’s spatial geometry, and novel methodologies have been developed for accurate spectral assessment. The ISBS linewidth was found to consistently decrease with increasing pump-beam diameter. These findings provide the means for improved spectral resolution measurements and pave the way to broader applications of ISBS microscopy.
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- Award ID(s):
- 2013771
- PAR ID:
- 10407488
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optics Express
- Volume:
- 31
- Issue:
- 9
- ISSN:
- 1094-4087; OPEXFF
- Format(s):
- Medium: X Size: Article No. 14604
- Size(s):
- Article No. 14604
- Sponsoring Org:
- National Science Foundation
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