All-optical phase conjugation using diffractive wavefront processing

Area of Science:

• Nonlinear optics
• Wavefront engineering
• Deep learning applications

Background:

• Optical phase conjugation (OPC) is crucial for correcting wavefront distortions in applications like imaging and beam focusing.
• Existing OPC methods can be complex or limited in scope.

Purpose of the Study:

• To develop an all-optical phase conjugation method using a diffractive wavefront processor.
• To leverage deep learning for optimizing diffractive layers to approximate OPC.

Main Methods:

• Utilized deep learning to design and optimize a set of diffractive layers.
• Experimentally fabricated the diffractive layers using 3D printing.
• Validated the processor's performance with terahertz radiation on unseen phase distortions.

Main Results:

• The diffractive wavefront processor successfully performed all-optical phase conjugation.
• The processor operated effectively through a shallow volume (tens of wavelengths).
• A diffractive phase-conjugate mirror was demonstrated by integrating diffractive layers with a standard mirror.

Conclusions:

• The developed diffractive wavefront processor offers a compact, passive, and multi-wavelength solution for aberration correction.
• This technology has potential applications in turbidity suppression and wavefront correction across various spectral bands.