  The orbital angular momentum (OAM) of light holds great promise for
applications in optical communication, super-resolution imaging, and
high-dimensional quantum computing. However, the spatio-temporal coherence of
the light source has been essential for generating OAM beams, as incoherent
ambient light would result in polychromatic and obscured OAM beams in the
visible spectrum. Here, we extend the applications of OAM to ambient lighting
conditions. By miniaturizing spiral phase plates and integrating them with
structural color filters, we achieve spatio-temporal coherence using only an
incoherent white light source. These optical elements act as building blocks
that encode both color and OAM information in the form of colorful optical
vortices. Thus, pairs of transparent substrates that contain matching positions
of these vortices constitute a reciprocal optical lock and key system. Due to
the multiple helical eigenstates of OAM, the pairwise coupling can be further
extended to form a one-to-many matching and validation scheme. Generating and
decoding colorful optical vortices with broadband white light could find
potential applications in anti-counterfeiting, optical metrology, high-capacity
optical encryption, and on-chip 3D photonic devices.
