Subwavelength hole arrays with nanoapertures fabricated by scanning probe nanolithography

Abstract

Owing to their surface plasmon-based operation, arrays of subwavelength holes show extraordinary electromagnetic transmission and intense field localizations of several orders of magnitude. Thus they were proposed as the basic building blocks for a number of applications utilizing the enhancement of nonlinear optical effects. We designed and simulated nanometer-sized subwavelength holes using an analytical approach. In our experiments we used the scanning probe method for nanolithographic fabrication of subwavelength hole arrays in silver layers sputtered on a positive photoresist substrate. We fabricated ordered nanohole patterns with different shapes, dispositions and proportions. The smallest width was about 60 nm. We characterized the fabricated samples by atomic force microscopy.

Zahvaljujući tome što im je funkcionisanje zasnovano na površinskim plazmonima, kod matrica šupljina subtalasnih dimenzija dolazi do izuzetno povećane elektromagnetske transmisije i intenzivne lokalizacije polja od nekoliko redova veličine. Zbog toga su takve strukture predložene kao osnovni gradivni blokovi za raznovrsne primene kod kojih se koristi pojačanje nelinearnih efekata. Koristeći analitički pristup, u ovom radu projektovali smo i simulirali matrice subtalasnih šupljina nanometarskih dimenzija. U našim eksperimentima koristili smo metodu skanirajuće sonde za nanolitografsku izradu matrica subtalasnih šupljina u srebrnim slojevima spaterovanim na supstratu od fotootpornog pozitiva. Napravili smo pravilno raspoređene nanošupljine različitih oblika, rasporeda i dimenzija, pri čemu je širina najmanjih bila oko 60 nm. Izrađene uzorke karakterisali smo AFM mikroskopijom.