Focusing light through scattering media by polarization modulation based generalized digital optical phase...

Area of Science:

• Biomedical Optics
• Wavefront Shaping
• Light Scattering

Background:

• Optical scattering limits light penetration in biological tissues beyond 1 mm.
• Digital optical phase conjugation (DOPC) and wavefront shaping are key to overcoming this limit.
• Existing DOPC systems use phase or amplitude modulation.

Purpose of the Study:

• To develop and validate a generalized DOPC technique using polarization modulation.
• To demonstrate efficient light focusing through thick scattering media.
• To utilize inexpensive and widely available spatial light modulators (SLMs).

Main Methods:

• Developed an algorithm to extract polarization maps from scattered light fields.
• Validated the algorithm using numerical simulations.
• Constructed an experimental setup with a liquid crystal SLM for polarization modulation.

Main Results:

• Polarization modulation achieved focusing contrast comparable to phase modulation.
• Successfully demonstrated light focusing through 3-mm thick chicken breast tissue.
• Showcased the effectiveness of inexpensive SLMs for wavefront shaping.

Conclusions:

• Polarization modulation is a viable and effective method for generalized DOPC.
• Inexpensive, high-pixel-count SLMs are suitable for advanced wavefront shaping applications.
• This technique offers a cost-effective solution for deep-tissue optical focusing.