Stimuli responsive diffraction gratings in soft-composite materials

Diffraction gratings (DGs) are unique optical components with the capability to control and address a travelling light wave because of their micro/nanoscale periodicity. Nowadays, DGs are used in several sophisticated and high-tech applications such as spectrometers, memories, as well as in bioengineering and telecommunications. Advanced micro and nano fabrication processes enable the realization of DGs with excellent morphological and optical properties. However, realizing DGs with on-demand optical parameters is still a challenge because of the absence of reliable and cost-effective smart materials. Herein, we discuss the unique and compelling opportunities obtained by bridging materials with intrinsic flexibility (soft polymers) and re-configurability (liquid crystals (LCs)), as well as emerging fabrication procedures. Further, we present several stimuli responsive DGs used in various research fields such as sensing, biotechnology and solar energy. Lastly, in the light of flexible and reconfigurable DGs applications, we report different examples of light responsive and electro-activated, LCs based, DGs.