Low voltage, highly tunable diffraction grating based on dielectric elastomer actuators

We present an electrically tunable diffraction grating, driven by thin-film dielectric elastomer actuators. The device combines the advantages of dielectric elastomer actuators, capable of generating very large strains, with the desirable properties of Micro-Opto-Electro-Mechanical Systems (MOEMS). The soft materials based tunable diffraction grating achieves a continuous grating period change of 19.2%, when a voltage of 500 V is applied. This is an improvement by a factor of 90 compared to conventional analog tunable diffraction gratings based on hard materials. Further device characterization yielded a tunable angular range of more than 100 mrad. Additionally, we show that in combination with a collimated white light source (e.g. white light emitting diode), the discussed tunable diffraction grating can be used for wavelength-adjustable luminous sources. Integrated into displays, these light sources could facilitate the first technology able to reproduce all perceivable colors.