Surface plasmon enhanced fluorescence sensor

A surface plasmon enhanced fluorescence sensor, comprising:

• i) an exciting light source, which produces exciting light having a predetermined wavelength λ1,
• ii) a dielectric material block, which has been formed from a material capable of transmitting the exciting light,
• iii) a metal film, which has been formed on one surface of the dielectric material block,
• iv) a sample support section for supporting a sample at a position in the vicinity of the metal film,
• v) an exciting light irradiating optical system for irradiating the exciting light through the dielectric material block toward an interface between the dielectric material block and the metal film, such that total reflection conditions may be satisfied, and
• vi) analysis fluorescence detecting means for detecting an intensity of analysis fluorescence having a wavelength λ2 and having been produced by an analysis fluorescent substance, which is contained in the sample, the analysis fluorescent substance producing the analysis fluorescence by being excited by an evanescent wave oozing out from the interface at the time at which the exciting light has impinged upon the interface,
• wherein the improvement comprises the provision of:
• a) a reference fluorescent substance, which is different from the analysis fluorescent substance and has been located at a position for excitation by the exciting light,
• b) reference fluorescence detecting means for detecting an intensity of reference fluorescence having a wavelength λ3 and having been produced by the reference fluorescent substance, where λ3≠λ2, and
• c) operation processing means for normalizing the intensity of the analysis fluorescence, which has been detected by the analysis fluorescence detecting means, in accordance with the intensity of the reference fluorescence, which has been detected by the reference fluorescence detecting means.