Synchronous-digitization for Video Rate Polarization Modulated Beam Scanning Second Harmonic Generation Microscopy.

Area of Science:

• Non-linear optics
• Optical microscopy
• Materials science

Background:

• Traditional polarimetry records only the exciting beam's polarization state.
• Characterizing polarization-dependent optical properties at high speeds is challenging.

Purpose of the Study:

• To develop a video-rate imaging technique for simultaneous nonlinear optical Stokes ellipsometry (NOSE) and linear Stokes ellipsometry.
• To enable recovery of the complex-valued Jones tensor describing polarization-dependent observables.

Main Methods:

• Coupling fast beam-scanning microscopy with 8 MHz polarization modulation and analytical modeling.
• Utilizing synchronous digitization (SD) synchronized to a master laser clock for video-rate acquisition (15 Hz).
• Processing image sets to recover Jones tensor elements for second harmonic generation (SHG) and fundamental beam transmittance.

Main Results:

• Achieved simultaneous NOSE and linear Stokes ellipsometry imaging at video rate (15 Hz).
• Successfully recovered complex-valued Jones tensor elements from polarization-dependent observables.
• Validated the approach using Z-cut quartz and applied it to naproxen micro-crystals.

Conclusions:

• The developed NOSE microscopy enables high-speed, detailed characterization of polarization-dependent optical properties.
• This technique offers a significant advancement over traditional polarimetry for materials analysis.
• Potential applications in various fields requiring rapid optical property mapping.