Optical Biosensor Using Near Infrared Laser for Enhancement of Detection Accuracy

This work presents the figures of merit of an optical sensor using a prism based on surface plasmon resonance (SPR). A combination of a prism coated with a thin Ag layer and a wavelength of 1064 nm was used for SPR excitation. The simulated results showed that the sensor coated with a Ag layer of 60 nm yielded good response with a detection accuracy of 14 times that obtained using a wavelength of 633 nm. The sensor using a wavelength of 1064 nm showed a quality factor of around 1027.4/degrees and a penetration depth of 384.4 nm, which were 9.3 times and 3.5 times better, respectively, than those obtained when using a wavelength of 633 nm. The enhancement of the detection accuracy and the penetration depth of the sensor using a wavelength of 1064 nm offer advantages for the detection of bio-targets in biomedical and food applications.