The invention relates to the technical field of optical element manufacturing, in particular to an
exposure device with an adjustable interference angle without other optical elements, an
exposure method and a preparation method of a reflective volume
grating. The
exposure device comprises a
laser source, a reflector, a beam expanding
system, a collimating lens, an optical rotating table and PTR glass, wherein the PTR glass is arranged on the optical rotating table; wherein
laser emitted by the
laser source passes through the reflector, is subjected to
light spot beam expansion through the beam expansion
system, and is subjected to
light beam collimation through the collimating lens, and then the
light beam enters the PTR glass body and is interfered in the PTR glass body to form interference fringes; by rotating the optical rotating table, a
light beam is incident into the PTR glass body at different angles, and interference fringes of different periods are formed by changing the interference angle. The interference angle is changed by adjusting the light incident angle, the reflective volume
grating with different wavelengths is prepared, interference can be automatically formed without depending on redundant optical components, and meanwhile the reflective volume
grating has the advantages of being low in cost, simple in structure, easy to operate, beneficial to large-scale production and the like.