Bessel-beam-written nanoslit arrays and characterization of their optical response

Şahin, Ramazan; Morová, Berna; Şimşek, Ergün; Aktürk, Selçuk

doi:10.1063/1.4805358

Cited by 16 publications

(10 citation statements)

References 18 publications

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“…The radiative lifetime in CQDs, an additional measurable observable that can indicate on coupling effects, is inversely proportional to the square of the overlap integral between the electron and hole 52 . The overlap integral for the lowest electron state and the highest hole state both for monomer and dimer and for both band offsets was calculated according to Eq.…”

Section: Please Cite This Article As Doi:101063/15128086mentioning

confidence: 99%

Electronic coupling in colloidal quantum dot molecules; the case of CdSe/CdS core/shell homodimers

Panfil

Shamalia

Cui

et al. 2019

The Journal of Chemical Physics

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Coupled colloidal quantum dot molecules composed of two fused CdSe/CdS core/shell sphere monomers were recently presented. Upon fusion, the potential energy landscape is changing into two quantum dots separated by a pre-tuned potential barrier with energetics dictated by the conduction and valence band offsets of the core/shell semiconductors, and width controlled by the shell thickness and the fusion reaction conditions. In close proximity of the two nanocrystals, orbital hybridization occurs, forming bonding and anti-bonding states in analogy to the hydrogen molecule. In this study we examine theoretically the electronic and optical signatures of such a quantum dot dimer compared to its monomer core/shell buildingblocks. We examine the effects of different core sizes, barrier widths, different band offsets and neck sizes at the interface of the fused facets, on the system wave-functions and energetics. Due to the higher effective mass of the hole and the large valence band offset, the hole still essentially resides in either of the cores breaking the symmetry of the potential for the electron as well. We found that the dimer signature is well expressed in a red shift of the band gap both in absorption and emission, in slower radiative lifetimes and in an absorption cross section which is significantly enhanced relative to the monomers at energies above the shell absorption onset, while remains essentially at the same level near the band-edge. This study provides essential guidance to pre-design of coupled quantum dot molecules with specific attributes which can be utilized for various new opto-electronic applications.As CQDs are often called "artificial atoms", two attached CQDs can form an artificial molecule. Such a homodimer CQDM is thus analogous to the hydrogen diatomic molecule in which, at a short distance between the hydrogen atoms, bonding and anti-bonding states form by the hybridization of the 1S states. While studies about the coupling of two dots grown by molecular beam epitaxy (MBE) methods have been done [33][34][35] , almost no such studies are reported for CQDMs. Importantly, the CQDMs are characterized by smaller size and enhanced quantum confinement effects relative to the MBE dots. This, combined with the ability to This is the author's peer reviewed, accepted manuscript. However, the online version of record will be different from this version once it has been copyedited and typeset. PLEASE CITE THIS ARTICLE AS

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Section: Please Cite This Article As Doi:101063/15128086mentioning

confidence: 99%

Electronic coupling in colloidal quantum dot molecules; the case of CdSe/CdS core/shell homodimers

Panfil

Shamalia

Cui

et al. 2019

The Journal of Chemical Physics

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“…Bessel/Bessel vortex beams yield a submicron central spot/central ring with an extended depth of focus simultaneously, and ultrafast lasers are capable of * Correspondence: ramazansahin@akdeniz.edu.tr damaging any kind of materials. Therefore, direct patterning of thin films [16,17], single-layer graphene [18][19][20], and bulk glasses [10] at nanoscale dimensions could be achieved by joining these two techniques together.…”

Section: Introductionmentioning

confidence: 99%

“…Considering its simplicity and energy efficiency, using conical lenses (axicons) is the most appropriate technique in order to convert Laguerre-Gaussian beams to Bessel beams [24]. Although the majority of experimental studies consist of producing zeroth-order Bessel beams [10,[16][17][18], recent studies show that higher-order Bessel beams [15,25,26] are of interest to the research community. Since zeroth order Bessel beams and higher-order Bessel beams possess different electric field profiles in the transverse plane, zeroth-order and higher-order beams are classified as Bessel beams and Bessel vortex beams, respectively.…”

Section: Introductionmentioning

confidence: 99%

Bessel and Bessel vortex beams generated by blunt-tip axicon

Şahin¹

2018

Turk J Phys

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A theoretical prediction of the propagation characteristics of Laguerre-Gaussian beams after passing through a blunt-tip axicon is presented. An ideal axicon generates theoretically perfect diffraction-free and smooth-on-axis intensity Bessel beams, while experiments and calculations show that a zeroth-order Bessel beam deviates from its perfect behavior. Strong intensity modulation occurs due to interference around the center of the beam. The origin of these oscillations should be explored to increase the quality of beam shaping. This research shows that these oscillations can be reduced by stopping the beam center for a small portion or by optimizing input beam parameters. On the other hand, since they have singularity at the beam center, higher-order Bessel beams would be affected less by the bluntness of the axicon. In order to prove this idea, a series of calculations with wavelengths of 1030, 515, and 343 nm were conducted. The tip of the axicon was modeled as a hyperbola with a base angle of 0.5 •. Our calculations indicate that zeroth-order Bessel beams are much more sensitive than the higher-order Bessel beams to axicon bluntness. Moreover, not only the axicon geometry and wavelength of the illuminating light, but also the input beam parameters are quite important when enhancing the quality of beam shaping.

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“…10 Our recent studies indicate that fs pulses with Bessel beam profiles provide significant advantages on thinfilm type structures. 13,14 In this work, we apply the Bessel beam nanostructuring method for patterning of graphene surfaces. One of the most convenient substrates for graphene is SiO 2 on Si, as it provides visibility of graphene layers even under an optical microscope.…”

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confidence: 99%

Nanoscale patterning of graphene through femtosecond laser ablation

Şahin

Şimşek

Aktürk

2014

Applied Physics Letters

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115

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Bessel-beam-written nanoslit arrays and characterization of their optical response

Abstract: Nanoslit arrays are fabricated on thin metal film coated glass slides using femtosecond laser pulses

Cited by 16 publications

References 18 publications

Electronic coupling in colloidal quantum dot molecules; the case of CdSe/CdS core/shell homodimers

Electronic coupling in colloidal quantum dot molecules; the case of CdSe/CdS core/shell homodimers

Bessel and Bessel vortex beams generated by blunt-tip axicon

Nanoscale patterning of graphene through femtosecond laser ablation

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