Emre Ozan Polat

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• Professor
• Professor (Assistant) at Bilkent University

Plasmonic nanostructures provide local field enhancement to be used as efficiency-boosting tools in fluorescence-based applications. For photostable quantum dots (QDs) to have enhanced emission, their size and exact location in the proximity of plasmonic nanostructure become key parameters while constructing light emitting devices. However, plasmon...

Decay rate of an atomic or molecular dipole depends on the local density of optical states (LDOS)-Purcell effect-which can significantly be enhanced near a dielectric-core metal-shell nanoparticle (CSNP). On top of that, an auxiliary quantum object (QO) can introduce a Fano transparency in the plasmonic spectrum of the CSNP. Here, we show that an a...

Integration of devices generating non-classical states (such as entanglement) into photonic circuits is one of the major goals in achieving integrated quantum circuits (IQCs). This is demonstrated successfully in recent decades. Controlling the non-classicality generation in these micron-scale devices is also crucial for the robust operation of the...

The development of new biosensor technologies and their active use as wearable devices have offered mobility and flexibility to conventional western medicine and personal fitness tracking. In the development of biosensors, transducers stand out as the main elements converting the signals sourced from a biological event into a detectable output. Com...

Health and fitness wearables present viable solutions for public wellbeing by providing remote personal control and clinical intervention through telemedicine networks. Due to their noninvasive and continuous vital sign monitoring, optoelectronic wearables are incorporated in number of studies to identify the onset and progression of the Coronaviru...

We asked young scientists to write an advertisement that answers this question: How will food options, food availability, and individuals' food choices change in the future? A selection of their suggested marketing campaigns is below. Follow NextGen Voices on Twitter with hashtag #NextGenSci. Read previous NextGen Voices survey results at https://s...

Wearable health and wellness trackers based on optical detection are promising candidates for public health uses due to their noninvasive tracking of vital health signs. However, so far, the use of rigid technologies hindered the ultimate performance and form factor of the wearable. Here, we demonstrate a new class of flexible and transparent weara...

We asked young scientists this question: How do broad interests benefit your science? Scientists with a variety of hobbies responded that their extracurricular activities have enhanced a wide range of skills, from creativity to communication to resilience. Many also mentioned the value of clearing their minds and relaxing. Follow NextGen and share...

The realization of optoelectronic devices on paper has been an outstanding challenge due to the large surface roughness and incompatible nature of paper with optical materials. Here, we demonstrate a new class of optoelectronic devices on a piece of printing paper using graphene as an electrically reconfigurable optical medium. Our approach relies...

We asked young scientists this question: What is your New Year's resolution for your fi eld? Describe one thing that your fi eld's research community could do better in the coming year. We received responses from scientists around the world representing a variety of fi elds. Excerpts of their responses are printed below.-Jennifer Sills must learn t...

Metamaterials bring subwavelength resonating structures together to overcome the limitations of conventional materials. The realization of active metadevices has been an outstanding challenge that requires electrically reconfigurable components operating over a broad spectrum with a wide dynamic range. However, the existing capability of metamateri...

Inspired by the work of the AAAS Science and Human Rights Coalition (AAAS is the publisher of Science), we asked young scientists this question: Describe how applications of knowledge in your field (information, methodologies, services, and/or products) could support civil, political, economic, social, or cultural rights. We received responses fro...

Tactile or electronic skin is needed to provide critical haptic perception to robots and amputees, as well as in wearable electronics for health monitoring and wellness applications. Energy autonomy of skin is a critical feature that would enable better portability and longer operation times. This study shows a novel structure, consisting of a tran...

The progress in the development of graphene devices is promising, and they are now considered as an option for the current Si-based electronics. However, the structural defects in graphene may strongly influence the local electronic and mechanical characteristics. Although there are well-established analytical characterization methods to analyze th...

The realization of optoelectronic devices on paper has been an outstanding challenge due to the large surface roughness and incompatible nature of paper with optical materials. Here, we demonstrate a new class of optoelectronic devices on a piece of printing paper using graphene as an electrically reconfigurable optical medium. Our approach relies...

Metamaterials bring sub-wavelength resonating structures together to overcome the limitations of conventional matter. The realization of active metadevices has been an outstanding challenge that requires electrically reconfigurable components operating over a broad spectrum with a wide dynamic range. The existing capability of metamaterials, howeve...

The financial support in the article “Broadband terahertz modulators using self-gated graphene capacitors” [J. Opt. Soc. Am. B 32, 1861 (2015)10.1364/JOSAB.32.001861JOBPDE0740-3224] was not fully acknowledged, and it is therefore corrected in this erratum.

This work demonstrates an attractive low-cost route to obtain large area and high-quality graphene films by using the ultra-smooth copper foils which are typically used as the negative electrodes in lithium-ion batteries. We first compared the electronic transport properties of our new graphene film with the one synthesized by using commonly used s...

Flexible electronics has huge potential to bring revolution in robotics and prosthetics as well as to bring about the next big evolution in electronics industry. In robotics and related applications, it is expected to revolutionise the way with which machines interact with humans, real-world objects and the environment. For example, the conformable...

We demonstrate a terahertz intensity modulator using a graphene supercapacitor which consists of two large-area graphene electrodes and an electrolyte medium. The mutual electrolyte gating between the graphene electrodes provides very efficient electrostatic doping with Fermi energies of 1 eV and a charge density of . We show that the graphene supe...

This paper presents a study into the electrical conductivity of multi-wall carbon nanotube-polydimethylsiloxane (MWNT-PDMS) nanocomposite and their dependence on the filler concentration. It is observed that the electrical conductivity of the composites can be tailored by altering the filler concentration. Accordingly, the nanocomposites with fille...

The latest advancements in electronic skin technology have attracted increasing attention for their potential to detect subtle pressure changes, which may open up applications including health monitoring, minimally invasive surgery, and prosthetics. Electronic sensory or tactile skin would help in enabling robots and similar machines to interact ph...

This work demonstrates the synthesis of high quality, single layer graphene on commercially available ultra-smooth copper foils. The presented method will result in improved scalability of graphene based electronic and optical devices. Our approach is compatible with roll-to-roll printing as well as transfer printing of graphene layers on to a broa...

In this Letter, we demonstrate a broadband terahertz (THz) spatial light modulator using arrays of large area graphene supercapacitors. Our approach relies on controlling spatial charge distribution on a passive matrix array of patterned graphene electrodes. By changing the voltage bias applied to the rows and columns, we were able to pattern the T...

Radar-absorbing materials are used in stealth technologies for concealment of an object from radar detection. Resistive and/or magnetic composite materials are used to reduce the backscattered microwave signals. Inability to control electrical properties of these materials, however, hinders the realization of active camouflage systems. Here, using...

Proton conducting gel electrolytes are very important component of clean energy devices. Phosphoric acid (PA, H3PO4•H2O) is one of the best proton conductor, but needs to be incorporated into some matrix for real device applications, such as into lyotropic liquid crystalline mesophases (LLCM). Herein, we show that PA and non-ionic sur-factant (NS,...

Graphene emerges as a viable material for optoelectronics because of its broad optical response and gate-tunable properties. For practical applications, however, single layer graphene has performance limits due to its small optical absorption defined by fundamental constants. Here, we demonstrated a new class of flexible electrochromic devices usin...

We report, for the first time to our knowledge, the demonstration of a graphene supercapacitor as a voltage-controlled saturable absorber for femtosecond pulse generation from a solid-state laser. By applying only a few volts of bias, the Fermi level of the device could be shifted to vary the insertion loss, while maintaining a sufficient level of...

For the first time to our knowledge, we employed a graphene supercapacitor as a voltage controlled saturable absorber at bias voltages of 0.5-1V to generate 84-fs pulses from a solid-state laser near 1255 nm.

In this letter we report gate-tunable X-ray photoelectron emission from back-gated graphene transistors. The back-gated transistor geometry allows us to study photoemission from graphene layer and the dielectric substrate at various gate voltages. Application of gate voltage electrostatically dopes graphene and shifts the binding energy of photoele...

Optical modulators are commonly used in communication and information technology to control intensity, phase or polarization of light. Electro-optic, electroabsorption and acousto-optic modulators based on semiconductors and compound semiconductors have been used to control the intensity of light. Due to gate tunable optical properties, graphene in...

Here we report chemical vapor deposition of graphene on gold surface at ambient pressure. We studied effects of the growth temperature, pressure and cooling process on the grown graphene layers. The Raman spectroscopy of the samples reveals the essential properties of the graphene grown on gold surface. In order to characterize the electrical prope...