An optical device generated by interferometric lithography, in the form of
a surface relief pattern that diffracts light, to be used mainly in
optical security, produced by optical systems compliant with the
Schimpflug and hinge Rules containing: two identical lenses L1 and L2,
two physical object location B1 e B2 and one image plane A1.ident.A2. No
physical mask is needed throughout the origination process, thus
eliminating any kind of border effects. The device actually implements an
in-plane focused hologram, with a complex surface pattern of valleys and
ridges with a non-trivial generating function, which is, by itself, both
an additional security feature of the device and its fingerprint. The
time to generate the optical device is proportional to the number of
colours specified for the reference geometry and not depend on the
overall area of the optical device.