Efficiently scanning a focus behind scattering media beyond memory effect by wavefront tilting and re-optimization.

Area of Science:

• Optics and Photonics
• Wavefront Shaping
• Light Propagation Through Scattering Media

Background:

• Controlling light propagation through scattering media is a significant challenge in wavefront shaping.
• The scanning range of foci generated by wavefront shaping is typically limited by the optical memory effect (ME).

Purpose of the Study:

• To propose and demonstrate an efficient method for scanning light foci beyond the ME region in scattering media.
• To enable controllable light propagation over extended ranges for applications requiring imaging through scattering materials.

Main Methods:

• Introduced the wavefront tilting and re-optimization (WFT&RO) method.
• Utilized wavefront tilting to initially scan the focus.
• Employed wavefront re-optimization using the scanned focus as a guide star to enhance intensity and accelerate optimization.

Main Results:

• Successfully demonstrated efficient scanning of a focus beyond the ME region in scattering media.
• Achieved scanning ranges at least 5-fold larger than the ME region for a single diffuser and 7-fold larger for two cascaded diffusers.
• Maintained relatively uniform focus intensity throughout the extended scanning range.

Conclusions:

• The WFT&RO method effectively overcomes the limitations of the optical memory effect for focus scanning in scattering media.
• This technique offers a promising solution for applications such as deep-tissue imaging and optical manipulation through opaque environments.
• The ability to scan foci over large distances with uniform intensity is crucial for advanced imaging and sensing applications.