Soft Tunable 3D Photonic Crystals

December 19, 2023

A groundbreaking method has surfaced for developing soft tunable 3D photonic crystals that control light in all directions. The introduction of nanoparticles into the blue phase liquid crystal paves the way for advanced photonic devices.

Fascinating World of Photonic Crystals

Similar to the captivating patterns in butterfly wings and peacock feathers, photonic crystals showcase mesmerizing optical properties. They serve as optical counterparts to semiconductors, manipulating light through refractive index contrasts along the direction of propagation. Photonic crystals can control light along a specific direction (incomplete photonic band gap) or in all directions (complete photonic band gap).

Fabrication Challenges

Creating 3D photonic crystals in the visible spectrum is challenging due to nanometer length scales, demanding sophisticated fabrication techniques.

Blue Phases as Alternatives

Highly chiral liquid crystals with blue phases (BPs) are explored as cost-effective alternatives to traditional 3D photonic crystals. The self-assembly of liquid crystal molecules in BPs realizes photonic properties, though they fall into the category of incomplete photonic band gap materials due to their small refractive index contrast.

A Pathway to Complete Photonic Bandgap

Cost-Effective Methodology: Researchers have developed a simple and cost-effective methodology involving the incorporation of high refractive index nanoparticles into the blue phase liquid crystal.

Enhancing Refractive Index Contrast: Spherical-shaped Selenium nanoparticles, with a high refractive index, strategically placed within defect cores of the blue phase, effectively increase the refractive index contrast, enhancing the photonic bandgap width.

Finite Element Method Simulations: Extensive Finite Element Method (FEM) simulations underscore that achieving a complete photonic bandgap system depends not only on refractive index contrast magnitude but also on the symmetry of the photonic crystal or blue phase.

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