Application of confocal surface wave microscope to self-calibrated attenuation coefficient measurement by Goos-Hänchen phase shift modulation

Pechprasarn, Suejit; Chow, Terry W. K.; Somekh, Michael G.

Abstract

In this paper, we present a direct method to measure surface wave attenuation arising from both ohmic and coupling losses using our recently developed phase spatial light modulator (phase-SLM) based confocal surface plasmon microscope. The measurement is carried out in the far-field using a phase-SLM to impose an artificial surface wave phase profile in the back focal plane (BFP) of a microscope objective. In other words, we effectively provide an artificially engineered backward surface wave by modulating the Goos Hänchen (GH) phase shift of the surface wave. Such waves with opposing phase and group velocities are well known in acoustics and electromagnetic metamaterials but usually require structured or layered surfaces, here the effective wave is produced externally in the microscope illumination path. Key features of the technique developed here are that it (i) is self-calibrating and (ii) can distinguish between attenuation arising from ohmic loss (k″ Ω ) and coupling (reradiation) loss (k″ c ). This latter feature has not been achieved with existing methods. In addition to providing a unique measurement the measurement occurs of over a localized region of a few microns. The results were then validated against the surface plasmons (SP) dip measurement in the BFP and a theoretical model based on a simplified Green’s function.

Citation

Pechprasarn, S., Chow, T. W. K., & Somekh, M. G. (2018). Application of confocal surface wave microscope to self-calibrated attenuation coefficient measurement by Goos-Hänchen phase shift modulation. Scientific Reports, 8, Article 8547. https://doi.org/10.1038/s41598-018-26424-2

• Journal Article Type: Article
• Acceptance Date: Apr 23, 2018
• Online Publication Date: Jun 4, 2018
• Publication Date: 2018-12
• Deposit Date: Oct 22, 2020
• Publicly Available Date: Oct 22, 2020
• Journal: Scientific Reports
• Electronic ISSN: 2045-2322
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 8
• Article Number: 8547
• DOI: https://doi.org/10.1038/s41598-018-26424-2
• Public URL: https://nottingham-repository.worktribe.com/output/4983250
• Publisher URL: https://www.nature.com/articles/s41598-018-26424-2
• Additional Information: Received: 16 February 2018; Accepted: 23 April 2018; First Online: 4 June 2018; : The authors declare no competing interests.