Holographic Control of Motive Shape in Plasmonic Nanogap Arrays

Abstract

Here we demonstrate that 4-beam holographic lithography can be utilized to create plasmonic nanogaps that are 70 times smaller than the laser wavelength (488 nm). This was achieved by controlling phase, polarization, and laser beam intensity in order to tune the relative spacing of the two sublattices in the interference pattern of a compound-lattice in combination with the nonlinear resist response. Exemplarily, twin and triplet motive features were designed and patterned into polymer in a single exposure step and then transferred into gold nanogap arrays resulting in an average gap size of 22 nm and smallest features down to 7 nm. These results extend the utility of high-throughput, wafer-scale holographic lithography into the realm of nanoplasmonics.

Fabrication of hierarchical nanostructures using free-standing trilayer membrane

“…The substrate was then exposed to form periodic nanopore patterns in a square array by using laser interference lithography. [35][36][37] The interference lithography systems and processes used in this study were especially developed for the large-area (i.e., full wafer-scale) nanopatterning, as reported earlier. 12,[38][39][40][41][42][43] In this work, the nanopore patterns of two different periods (500 and 900 nm) were prepared by using a He-Cd laser of a wavelength of 325 nm (IK3501R-G, Kimmon Koha Co., Ltd.).…”

Fabrication of Complex Micro/Nanopatterns on Semiconductors by the Multi-beam Interference of Femtosecond Laser

“…The number and spatial arrangement of interfering beams determine mainly intensity patterns. Laser polarization and phase also play important roles in interference patterns and are usually manipulated to improve the aspect ratio of periodic structures [3][4][5][6]. By adjusting the polarization and phase of laser beams, different microstructures, such as compound photonic crystals, magnetic metamaterials and plasmonic nanogap array, have been fabricated.…”

Holographic fabrication of nano-optical devices using single reflective optical element

“…In particular this method has also been applied for the fabrication of nano-antennas. Recent progress in this field has demonstrated the fabrication of plasmonic nanogaps that are 70 times smaller than the laser wavelength (488 nm) using 4-beam holographic lithography [23]. This was achieved by controlling phase, polarization, and laser beam intensity in order to tune the relative spacing of the two sub-lattices in the interference pattern of a compound lattice.…”

“…The lattice symmetries and basis are controlled by the number of interfering beams, their amplitudes, respective polarizations, relative phases, and wave vector configurations [13][14][15][16][17][18][19][20][21][22][23][24][25]. The downside of holographic lithography is that the optical setup for the multi-beam interference can become very complicated when bulky mirrors, beam polarizers, and beam splitters are used for the control of the wave parameters [5,6].…”