Browsing by Author "Memisoglu, G."

Now showing 1 - 4 of 4

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CSSTag: optical nanoscale radar and particle tracking for in-body and microfluidic systems with vibrating graphene and resonance energy transfer
(IEEE, 2017-12) Gülbahar, Burhan; Memisoglu, G.; Electrical & Electronics Engineering; GÜLBAHAR, Burhan Cahit
Biological particle tracking systems monitor cellular processes or particle behaviors with the great accuracy. The emissions of fluorescent molecules or direct images of particles are captured with cameras or photodetectors. The current imaging systems have challenges in detection, collection, and analysis of imaging data, penetration depth, and complicated set-ups. In this paper, a signaling-based nanoscale acousto-optic radar and microfluidic multiple particle tracking (MPT) system is proposed based on the theoretical design providing nanoscale optical modulator with vibrating Förster resonance energy transfer and vibrating cadmium selenide/zinc sulfide quantum dots (QDs) on graphene resonators. The modulator combines significant advantages of graphene membranes having wideband resonance frequencies with QDs having broad absorption spectrum and tunable properties. The solution denoted by chirp spread spectrum (CSS) Tag utilizes classical radar target tracking approaches in nanoscale environments based on the capabilityto generate CSS sequences identifying different bio-particles. Monte Carlo simulations show significant performance for MPT with a modulator of 10 μm × 10 μm × 10 μm dimension and several picograms of weight, the signal-to-noise ratio in the range from -7 to 10 dB, simple light emitting diode sources with power less than 4 W/cm2 and high speed tracking for microfluidic environments.
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Nanoscale optical communications modulator and acousto-optic transduction with vibrating graphene and resonance energy transfer
(IEEE, 2017) Gülbahar, Burhan; Memisoglu, G.; Electrical & Electronics Engineering; GÜLBAHAR, Burhan Cahit
Graphene resonators are future promising in terms of ultra-low weight, high Young's modulus, strength and wideband resonance frequencies. Besides that, nanoscale optical wireless channels including visible light spectrum are alternatives to radio-frequency communications promising energy efficiency and high data rates. In this article, vibrating multi-layer graphene nanoelectromechanical resonators are combined with designed vibrating Forster resonance energy transfer (VFRET) mechanism to achieve a nanoscale acousto-optic modulator converting vibrations to multi-color photon emissions. The frequency, color and the vibration sensitivity of emission are tunable while vibrations are realized either passively or actively by exploiting acoustic, thermo-acoustic or opto-acoustic properties of graphene. The light is generated by FRET mechanism with oscillating donor-acceptor distance where donor molecules attached on graphene are chosen as CdSe/ZnS core-shell QDs with significant properties of broad absorption spectrum, large cross-sections, tunable emission spectra, size dependent emission wavelength, high photochemical stability and improved quantum yield. The designed modulator achieves acoustic and ultrasound frequencies between several KHz and tens of MHz and radiation power reaching several nanowatts with resonator sizes of hundreds of micrometers for ambient light intensity of 0.1 W/m2/nm. The proposed system promises significant applications including nanoscale acousto-optic communication, transduction, sensing, energy harvesting and biomedical nanoscale communications.
Open Access
Preparation and characterization of freely-suspended graphene nanomechanical membrane devices with quantum dots for point-of-care applications
(MDPI, 2020-01-01) Memisoglu, G.; Gülbahar, Burhan; Fernandez Bello, R.; Electrical & Electronics Engineering; GÜLBAHAR, Burhan Cahit
We demonstrate freely suspended graphene-based nanomechanical membranes (NMMs) as acoustic sensors in the audible frequency range. Simple and low-cost procedures are used to fabricate NMMs with various thicknesses based on graphene layers grown by graphite exfoliation and solution processed graphene oxide. In addition, NMMs are grafted with quantum dots (QDs) for characterizing mass sensitive vibrational properties. Thickness, roughness, deformation, deflection and emissions of NMMs with attached QDs are experimented and analyzed by utilizing atomic force microscopy, Raman spectroscopy, laser induced deflection analyzer and spectrophotometers. Forster resonance energy transfer (FRET) is experimentally achieved between the QDs attached on NMMs and nearby glass surfaces for illustrating acousto-optic utilization in future experimental implementations combining vibrational properties of NMMs with optical emission properties of QDs. This property denoted as vibrating FRET (VFRET) is previously introduced in theoretical studies while important experimental steps are for the first time achieved in this study for future VFRET implementations. The proposed modeling and experimental methodology are promising for future novel applications such as NMM based biosensing, photonics and VFRET based point-of-care (PoC) devices.
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Quantum spatial modulation of optical channels: Quantum boosting in spectral efficiency
(IEEE, 2019-11) Gülbahar, Burhan; Memisoglu, G.; Electrical & Electronics Engineering; GÜLBAHAR, Burhan Cahit
Spatial modulation (SM) improves spectral efficiency (SE) by creating the constellation of active optical antenna indices. However, quantum properties of light are not exploited to improve the SE. In this letter, multi-plane diffraction (MPD) set-up creating exponentially increasing number of propagation paths for classical sources is exploited to introduce quantum spatial modulation (QSM). Exponential number of paths and quantum superposition-based classical symbol generation for transmitting simultaneous multiple classical symbols are exploited for linear and exponential quantum boosting of SM, respectively. It is theoretically modeled, numerically analyzed, and the challenges of joint design of source-channel coding and QSM are discussed.