Highly sensitive differential phase-sensitive surface plasmon resonance biosensor based on the Mach-Zehnder configuration

S. Y. Wu, H. P. Ho, Wing Cheung Law, Chinlon Lin, S. K. Kong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

271 Citations (Scopus)


A high-sensitivity surface plasmon resonance (SPR) biosensor based on the Mach-Zehnder interferometer design is presented. The novel feature of the new design is the use of a Wollaston prism through which the phase quantities of the p und s polarizations are interrogated simultaneously. Since SFR affects only the p polarization, the signal due to the s polarization can be used as the reference. Consequently, the differential phase between the two polarizations allows us to eliminate all common-path phase noise while keeping the phase change caused by the SPR effect. Experimental results obtained from glycerin-water mixtures indicate that the sensitivity limit of our scheme is 5. 5 × 10-8 refractive-index units per 0.01° phase change. To our knowledge, this is a significant improvement over previously obtained results when gold was used as the sensor surface. Such an improvement in the sensitivity limit should allow SPR biosensors to become a possible replacement for conventional biosensing techniques based on fluorescence. Monitoring of the bovine serum albumin. (BSA) binding reaction with. BSA antibodies is also demonstrated.
Original languageEnglish
Pages (from-to)2378-2380
Number of pages3
JournalOptics Letters
Issue number20
Publication statusPublished - 15 Oct 2004
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this