\nTraditional gold plasmonics are confined to the near-infrared because gold’s high free-electron density fixes its plasma frequency far above the range needed for longer-wavelength applications, limiting surface plasmon-polariton (SPP) support to short wavelengths. Metaplasmonics addresses this limitation by patterning 30 nm-thick gold films with periodic subwavelength perforations that effectively dilute the free-electron density and extend the SPP support into the mid-infrared. Two gold grids with distinct short and long-axis periodicities (dx = 120 nm, dy = 800 nm) and staggering (Pattern 1: 0% stagger, Pattern 2: 50% stagger) were imaged using scattering-type scanning near-field optical microscopy (s-SNOM), which focuses light onto an ultra-sharp tip to achieve ~20 nm spatial resolution and resolve sub-diffractional SPP wavelengths. Real-space s-SNOM scans and their corresponding momentum-space maps revealed clear, frequency-dependent SPP dispersion consistent with prior simulations when illuminated parallel to the long axis, which launches SPP propagation along the short axis, or perpendicular to the incident illumination. Illumination parallel to the short axis, which launches SPPs in the long axis, produced comparatively less defined, near light-line fringes, indicating anisotropy in SPP dispersion between the two axes. This anisotropy may arise because the propagating SPP experiences different levels of free-electron dilution dependent on the axis in which it propagates. These findings demonstrate that periodic metaplasmonic geometry can be used to tune both the resonance frequency and directionality of plasmon-polariton propagation in gold, establishing a foundation for easily producible plasmonic devices for specialized mid-infrared use cases.<\/p>\n
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Shubh is an undergraduate researcher in the Department of Mechanical Engineering at Vanderbilt University, currently completing a Vanderbilt Institute of Nanoscale Science and Engineering (VINSE) Research Experience for Undergraduates (REU) program in Professor Joshua D. Caldwell’s Nanophotonic Materials and Devices Lab. His research uses sub-diffractional near-field microscopy to image and characterize confined surface plasmon-polariton propagation in gold metaplasmonics, alongside his mentors Mackey Long and Dr. Maximilian Obst and in collaboration with the Wasserman Mid-IR Photonics Lab at the University of Texas at Austin. He is currently a rising freshman, pursuing a degree in Mechanical Engineering at Vanderbilt University where he is also a Cornelius Vanderbilt scholarship recipient. He plans to pursue a career in nanophotonics or a related field following completion of his undergraduate degree.<\/p>\n","protected":false},"excerpt":{"rendered":"
Way to go Shubh for winning best poster award! Near-Field Characterization of Infrared Metaplasmonics: Mapping Tunable Plasmon Polaritons in Perforated Gold Films Traditional gold plasmonics are confined to the near-infrared because gold’s high free-electron density fixes its plasma frequency far above the range needed for longer-wavelength applications, limiting surface plasmon-polariton (SPP) support to short wavelengths….<\/p>\n","protected":false},"author":10000,"featured_media":1265,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1262","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"_links":{"self":[{"href":"https:\/\/my.vanderbilt.edu\/caldwellgroup\/wp-json\/wp\/v2\/posts\/1262","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/my.vanderbilt.edu\/caldwellgroup\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/my.vanderbilt.edu\/caldwellgroup\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/my.vanderbilt.edu\/caldwellgroup\/wp-json\/wp\/v2\/users\/10000"}],"replies":[{"embeddable":true,"href":"https:\/\/my.vanderbilt.edu\/caldwellgroup\/wp-json\/wp\/v2\/comments?post=1262"}],"version-history":[{"count":3,"href":"https:\/\/my.vanderbilt.edu\/caldwellgroup\/wp-json\/wp\/v2\/posts\/1262\/revisions"}],"predecessor-version":[{"id":1267,"href":"https:\/\/my.vanderbilt.edu\/caldwellgroup\/wp-json\/wp\/v2\/posts\/1262\/revisions\/1267"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/my.vanderbilt.edu\/caldwellgroup\/wp-json\/wp\/v2\/media\/1265"}],"wp:attachment":[{"href":"https:\/\/my.vanderbilt.edu\/caldwellgroup\/wp-json\/wp\/v2\/media?parent=1262"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/my.vanderbilt.edu\/caldwellgroup\/wp-json\/wp\/v2\/categories?post=1262"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/my.vanderbilt.edu\/caldwellgroup\/wp-json\/wp\/v2\/tags?post=1262"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}