Annular pupil confocal Brillouin-Raman microscopy for high spectral resolution multi-information mapping

Area of Science:

• Spectroscopy
• Microscopy
• Materials Science

Background:

• Brillouin-Raman combined confocal spectroscopy offers non-contact analysis of material properties.
• Current limitations in spectral and spatial resolution hinder advanced applications.
• High-numerical-aperture objectives cause spectral broadening, reducing Brillouin spectral resolution.

Purpose of the Study:

• To propose and demonstrate an annular pupil confocal Brillouin-Raman microscopy (APCBRM) scheme.
• To achieve simultaneous high-spectral-resolution Brillouin detection and high-lateral-resolution mapping.
• To enable 3D topography mapping alongside chemical and mechanical property analysis.

Main Methods:

• Implementation of an annular pupil in confocal Brillouin-Raman microscopy.
• Utilizing the annular pupil to suppress spectral broadening and compress the excitation spot.
• Employing a high-precision confocal focusing system for real-time scanning and 3D topography.

Main Results:

• Achieved a 22.1% reduction in the full width at half maximum of the Brillouin spectrum, enhancing spectral resolution.
• Increased lateral resolutions to approximately 353.2 nm for Brillouin and 347.1 nm for Raman spectroscopy.
• Demonstrated simultaneous high lateral and Brillouin spectral resolution, along with 3D topography mapping.

Conclusions:

• The APCBRM scheme significantly improves spectral and spatial resolution in combined spectroscopy.
• APCBRM offers a powerful tool for detailed material characterization.
• Potential applications span novel materials, precision machining, and biomedical imaging.