Fast Response Variable Focal-Length Lenses Using KTa1-xNbxO3Crystals

We fabricated variable focal length lenses with fast responses by using the strong Kerr effect of KTa1-xNbxO3 single crystals. We observed focus shifts of about 40 mm with the assistance of a 250-mm-focal-length lens, which corresponds to a focus shift from infinity to 1.56 m without the assisting lens. The time response was as fast as 1 µs.