title: Observation of giant Goos-Hänchen and angular shifts at designed metasurfaces.
abstract: Metasurfaces with sub-wavelength features are useful in modulating the phase, amplitude or polarization of electromagnetic fields. While several applications are reported for light manipulation and control, the sharp phase changes would be useful in enhancing the beam shifts at reflection from a metasurface. In designed periodic patterns on metal film, at surface plasmon resonance, we demonstrate Goos-Hanchen shift of the order of 70 times the incident wavelength and the angular shifts of several hundred microradians. We have designed the patterns using rigorous coupled wave analysis (RCWA) together with S-matrices and have used a complete vector theory to calculate the shifts as well as demonstrate a versatile experimental setup to directly measure the shifts. The giant shifts demonstrated could prove to be useful in enhancing the sensitivity of experiments ranging from atomic force microscopy to gravitational wave detection.
authors.affiliation: DCMP &MS, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 INDIA.
authors.forename: Venkata Jayasurya
authors.initials: VJ
authors.lastname: Yallapragada
authors.affiliation: DCMP &MS, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 INDIA.
authors.forename: Ajith P
authors.initials: AP
authors.lastname: Ravishankar
authors.affiliation: DCMP &MS, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 INDIA.
authors.forename: Gajendra L
authors.initials: GL
authors.lastname: Mulay
authors.affiliation: Department of Physics, Oklahoma State University, Stillwater, OK 74078, USA.
authors.forename: Girish S
authors.initials: GS
authors.lastname: Agarwal
authors.affiliation: DCMP &MS, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 INDIA.
authors.forename: Venu Gopal
authors.initials: VG
authors.lastname: Achanta