Abstract: In one embodiment, an apparatus for measuring pressure is provided including a holographic element containing at least one volume hologram; a reference member; a sensing member coupled to the pressure being measured, and at least one light source; wherein the device operates by passing a reference light beam between the reference member and the holographic element, the reference beam having a constant optical path, and passing a sensing light beam between the sensing member and the holographic element, the sensing beam having optical path that varies as a function of the pressure; the volume hologram converting the reference beam and the sensing beam into an information light beam the intensity of which is a measure of the pressure. Preferably, the reference member and the sensing member are made from the same material.