Strong Second Harmonic Generation and Nonlinear Optical Activity in Chiral Supramolecular Polymers

Area of Science:

• Nonlinear optics
• Materials science
• Photonics

Background:

• Advanced optical materials are crucial for new technologies.
• Chiral supramolecular structures offer exceptional second-order optical susceptibility (χ⁽²⁾).

Purpose of the Study:

• Investigate the origin and optical activity of second harmonic generation (SHG) in chiral polybinaphthalenes.
• Evaluate their potential for chiral photonics applications.

Main Methods:

• Utilized femtosecond laser pulses to study SHG in chiral polybinaphthalenes.
• Performed structural analysis and simulations.
• Employed lock-in amplifier detection for optical activity measurements.

Main Results:

• Achieved high χ⁽²⁾ values up to 7 pm/V, influenced by polymer backbone chromophores.
• Observed rodlike/helical structures promoting directional SHG signals.
• Linked SHG to quasi-phase matching and demonstrated high optical activity due to robust chiral structures.

Conclusions:

• Chiral polybinaphthalenes demonstrate significant SHG and optical activity.
• These supramolecular structures are excellent candidates for advanced chiral photonics applications.