Photonic band structure of cholesteric elastomers

Area of Science:

• Materials Science
• Optics
• Polymer Science

Background:

• Cholesteric elastomers are self-assembling polymers with tunable optical properties.
• Their photonic band structure, responsible for color and lasing, is sensitive to mechanical strain.

Purpose of the Study:

• To calculate the photonic band structure of cholesteric elastomers.
• To investigate the effect of strain on these band structures and their optical properties.
• To explore the potential for low-threshold lasing.

Main Methods:

• Photonic band structure calculations along and oblique to the helix axis.
• Analytical methods to determine strain-dependent scaling of stop bands.

Main Results:

• Strain significantly alters the photonic band structure, opening new stop bands and shifting frequencies.
• A "total" stop band for both circular polarizations was predicted.
• Stop bands extending to various angles create pseudogaps.

Conclusions:

• Strain engineering offers precise control over the optical properties of cholesteric elastomers.
• The predicted tunable stop bands and pseudogaps are relevant for achieving low-threshold lasing applications.