Wavelength-multiplexing phase-sensitive surface plasmon imaging sensor

A wavelength-multiplexing phase-sensitive surface plasmon resonance (SPR) imaging sensor offering wide dynamic detection range and microarray capability is reported. Phase detection is accomplished by performing self-interference between the s- and p- polarizations within the signal beam. A liquid crystal tunable filter is used to sequentially select the SPR excitation wavelength from a white light source. This wavelength-multiplexing approach enables fast detection of the sensor's SPR phase response over a wide range of wavelengths, thereby covering literally any regions of interest within the SPR dip and thus maintaining the highest sensitivity point at all times. The phase-sensitive approach is particularly important for imaging SPR sensing applications because of its less stringent requirements for intensity signal-to-noise ratio, which also means the possibility of using uncooled modest resolution analog-to-digital conversion imaging devices. Experimental results demonstrate a resolution of 2.7 × 10-7RIU with a dynamic range of 0.0138 RIU.