Method and apparatus for measuring pressure

An apparatus for measuring pressure comprising:

• a) a light source capable of emitting at least one primary light beam;
• b) a reference member having a reference surface;
• c) a moving member having a sensing surface and a load surface, said moving member capable of movement or displacement the magnitude of which is a function of pressure applied onto said load surface of said moving member;
• d) a holographic element having at leas one volume hologram located in alignment with said light source, the distance between said at least one volume hologram and said reference surface being substantially constant;
• and
• e) at least one signal detector;
• wherein, in operation of said apparatus, said at least one volume hologram splits said at least one primary light beam into a first secondary beam and a second secondary beam directed respectively onto said sensing surface of said moving member and said reference surface,
• wherein said first and second secondary beams are reflected thereby providing respectively a sensing beam having an optical path that changes as a function of pressure applied onto the load surface of said moving member, and a reference beam having a substantially constant optical path,
• said sensing beam and said reference beam being reflected toward said at least one volume hologram herein said sensing beam and said reference beam interact thereby providing at least one information beam being detected by said at least one signal detector.

An apparatus or measuring pressure comprising:

• a. a light source capable of emitting at least one primary light beam;
• b. a reference member having a reference surface;
• c. a stationary member having a beam-return surface;
• d. an optically-transparent photo-elastic element having a load surface, said photo-elastic element possessing an index of refraction that changes as a function of pressure applied onto said load surface;
• e. a holographic element having at least one volume hologram located in alignment with said light source, the distance between said at least one volume hologram and said reference surface being substantially constant;
• and
• f. at least one signal detector;
• wherein, in operation of said apparatus, said at least one volume hologram splits said at least one primary light beam into a first secondary beam and a second secondary beam;
• said first secondary beam being directed onto said beam-return surface that reflects said first secondary beam thereby providing a sensing beam, at least one of said first secondary beam and said sensing beam passing through said optically-transparent photo-elastic element thereby said sensing beam has an optical path that is a function of pressure applied onto the load surface of said photo-elastic element,
• said second secondary beam being directed onto said reference surface and being reflected thereby providing a reference beam having a substantially constant optical path,
• said sensing beam and said reference beam being reflected toward said at least one volume hologram wherein said sensing beam and said reference beam interact thereby providing at least one information beam being detected by said at least one signal detector.