Bessel-beam-written nanoslit arrays and characterization of their optical response – May 2013
R Sahin, Y Morova, E Simsek, S Akturk – Applied Physics Letters, Vol 102(19), 2013.
Nanoslit arrays are fabricated on thin metal film coated glass slides using femtosecond laser pulses with Bessel beam profiles. The optical properties of the fabricated structures with different periodicities are characterized with transmission spectroscopy. Experimental results reveal the existence of two separate surface plasmon resonance modes occurring at the metal-air and metal-glass interfaces. These two resonance modes cause two minima in the high transmission spectra of the sub-skin depth thick thin films in the visible and near infrared regions. The existence of double surface plasmon resonance modes is verified with additional experiments, theoretical and numerical studies. Due to its relaxed alignment constraints, reduced aberrations, scalability property to shorter wavelengths, and resulting shorter dimensions, nanofabrication with diffraction-free Bessel beams is an easy, cheap, and advantageous alternative to regular lithography techniques to fabricate nanoslit arrays. The shift of the resonance wavelength with a change in the refractive index of the surrounding medium can be exploited for enhanced sensing … 2 of Ref. The light source is a tungsten halogen lamp (StellarNet SL1), which is focused into an optical fiber. Fiber output is collimated by a microscope objective, goes through a Glan-Taylor polarizer, and illuminates the samples (from the metal side) at a diameter of 3 mm
