Near-Field Optical Microscopy

We observe an enhancement of fluorescence from a single fluorescent sphere, which is sandwiched between two individual gold nanoparticles, forming a hot spot of strong field enhancement. The fluorescence enhancing hot spot is custom-designed by the deliberate assembly of gold nanoparticles with an atomic force microsc…

• ALPAN BEK

An expandable system has been developed to operate multiple probes for the atomic force microscope in parallel at high speeds. The combined improvements from parallelism and enhanced tip speed in this system represent an increase in throughput by over two orders of magnitude. A modular cantilever design has been repli…

The speed of tapping mode imaging with the atomic force microscope (AFM) has been increased by over an order of magnitude. The enhanced operation is achieved by (1) increasing the instrument’s mechanical bandwidth and (2) actively controlling the cantilever’s dynamics. The instrument’s mechanical bandwidth is increase…

We present a 4 mm2 image taken with a parallel array of 10 cantilevers, an image spanning 6.4 mm taken with 32 cantilevers, and lithography over a 100 mm2 area using an array of 50 cantilevers. All of these results represent scan areas that are orders of magnitude larger than that of a typical atomic force microscope…

A mode of atomic force microscopy (AFM) is demonstrated where an oscillating AFM cantilever having linear response is driven with two frequencies in the vicinity of a resonance. New frequencies in the response, known as intermodulation products, are generated when the linearity of the cantilever response is perturbed…

• DEVRİM PESEN OKVUR

Analytical formula is derived for the M(2)-factor of coherent and partially coherent dark hollow beams (DHB) in turbulent atmosphere based on the extended Huygens-Fresnel integral and the second-order moments of the Wigner distribution function. Our numerical results show that the M(2)- factor of a DHB in turbulent at…

We report on the implementation of a versatile dynamic mode apertureless scanning near field optical microscope (aSNOM) for nanoscopic investigations of optical properties at surfaces and interfaces. The newly developed modular aSNOM optomechanical unit is essentially integrable with a multitude of laser sources, home…

• ALPAN BEK

5.3 million American couples of reproductive age (9%) are affected by infertility, among which male factors account for up to 50% of cases, which necessitates the identification of parameters defining sperm quality, including sperm count and motility. In vitro fertilization (IVF) with or without intra cytoplasmic sper…

• HASAN ONUR KELEŞ

We investigate the ability of the bow-tie slot antenna to generate intense optical spots below the diffraction limit. A commercially available finite-difference time-domain electromagnetic modelling software is used in the numerical simulations. The finite-difference time-domain software is first compared to analytica…

• İBRAHİM KÜRŞAT ŞENDUR

Sizing individual nanoparticles and dispersions of nanoparticles provides invaluable information in applications such as nanomaterial synthesis, air and water quality monitoring, virology, and medical diagnostics. Several conventional nanoparticle sizing approaches exist; however, there remains a lack of high-throughp…

Sub-50 nm lines, holes, and posts have been patterned photolithographically using near-field embedded-amplitude masks and an exposing wavelength of 220 nm generated by an arc-lamp source. Interference in the optical near field is utilized to produce the fine patterns. In some cases, the feature sizes on the mask are m…

• HAMİDE KAVAK

The performance of the ridge waveguide as a near-field aperture in data storage systems is investigated. Finite element method (FEM) and finite-difference time-domain (FDTD) based software are used in the numerical simulations. To verify their accuracy at optical frequencies, the FEM and FDTD are first compared to ana…