Amplification of ultrafast-rotating ring-shaped optical lattices

A superposition of two optical vortices with different topological charges forms a light wave with azimuthally periodic structure. The beam with such rotational symmetry is called a ring-shaped optical lattice [1]. One of its important features is that it can be flexibly rotated by controlling relative phase difference between them without changing its structure, which offers us rotational degree of freedom in applications such as optical manipulation of micro-or nano-particles. Conventionally, the rotational control has been realized by utilizing mechanical rotation of waveplates, acousto-optic devices or electro-optic modulators. However, their maximum rotational frequency has been limited to GHz regime owing to their response time or bandwidth.