Line-scanning Brillouin microscopy with multiplexed two-stage VIPA spectrometer

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• Materials Science

Background:

• Confocal Brillouin microscopy offers high-resolution mechanical imaging but suffers from slow acquisition speeds.
• Line-scanning Brillouin microscopy (LSBM) accelerates imaging using multiplexing but is hindered by noise and requires gas chambers for light suppression.
• Existing LSBM methods necessitate specific tunable lasers locked to gas absorption lines, limiting wavelength flexibility.

Purpose of the Study:

• To develop a novel multiplexed Brillouin spectrometer for LSBM that enhances noise suppression without a gas chamber.
• To overcome the limitations of single-stage virtually imaged phased array (VIPA) spectrometers in LSBM.
• To enable gas-chamber-free LSBM implementation across various wavelengths with readily available lasers.

Main Methods:

• Developed a cascaded two-stage VIPA etalon spectrometer with parallel dispersion axes.
• The first VIPA functions as a band-pass filter, and the second as a spectrum analyzer.
• Integrated the spectrometer into an inverted co-axial LSBM setup for imaging.

Main Results:

• Achieved a noise suppression of 57 dB, significantly improving signal quality.
• Successfully acquired Brillouin images of bio-printed phantoms using the gas-chamber-free LSBM system.
• Demonstrated the capability to operate without an absorptive gas chamber and specialized tunable lasers.

Conclusions:

• The developed multiplexed Brillouin spectrometer enhances LSBM performance by increasing noise suppression and eliminating the need for gas chambers.
• This advancement facilitates the adoption of LSBM at different wavelengths, particularly where Brillouin scattering is more efficient and commercial lasers are accessible.
• The gas-chamber-free approach broadens the applicability of high-resolution mechanical imaging in various scientific fields.