We demonstrated an infrared variable focus ionic liquids lens using electrowetting, which could
overcome the problems caused by use of water, e.g., evaporation and poor thermostability, while
keeping good optical transparency in visible light and near-infrared region. Besides, the type of
lens (convex or concave) could be tuned by applied voltage or refractive index of ILs used, and the
transmittance was measured to exceed 90% over the spectrum of visible light and near-infrared.
We believe this infrared variable focus ionic liquids lens has a great application prospect in both
visible light and infrared image systems.