Phase extraction method for phase type SPR (Surface Plasmon Resonance) planar array sensor

The invention discloses a phase extraction method for a phase type SPR planar array sensor. The method comprises the steps of splitting emergent light carrying SPR phase information into two beams of identical light perpendicular to each other in a propagation direction with a light beam splitter, obtaining interference light of P light and S light with one beam of light via an analyzer, imaging on a first CCD (Charge Coupled Device) via a first imaging lens, dividing into the P light and the S light perpendicular to each other in a propagation direction with the other beam of light via a light polarization beam splitter, imaging on corresponding CCDs via another two imaging lenses, obtaining light intensity values of the three CCDs at a certain definite point on a sensing plane: interference light intensity I of the P light and the S light, light intensity I[p] of the P light and light intensity I[s] of the S light, and obtaining a phase difference according to a formula. The method can directly extract the phase difference without addition of the traditional phase modulator, and overcomes the disadvantages of poor LCM (Liquid Crystal Module) temperature stability, poor PZT (Piezoe-lectric Transducer) earthquake resistance, high PEM (Pulse Encode Modulation) price and the like of the traditional phase modulator.