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Öğe Color filter effects on the performance of monocrystalline and polycrystalline photovoltaic solar panels(İlker ÖRS, 2023) Gökçen, Sündüz; Kaya, NecatiWe evaluated effect of different color filters on the electric production performance of monocrystalline and polycrystalline solar photovoltaic panels in real outdoor environment. In the experiment, we used four different color filters from blue to red on photovoltaic panels to observe energy and efficiency performance of the mono and polycrystalline solar photovoltaic panels as well as temperature of the panels measured with and without filters. We observed the wavelength dependence of monocrystalline photovoltaic panel is more effective than the polycrystalline photovoltaic panel one. For both panels we see that yellow color filtered produced the highest power value and have the lowest temperature value. This can be explained with that the spectrum of yellow color filter covers most of the radiation of solar but blocking infrared and ultraviolet side of the sun spectrum. This also causes the lower panel temperature. On the other hand, we observed that photovoltaic panels with blue color filter have the highest temperature value and the lowest power value. By the study we suggest that by optimizing the semiconductor band gaps in photovoltaic panels respect to solar wavelength, one can produce photovoltaic panels with higher efficiency by using filters, especially in hot climate regions. We expected that the results will also contribute to a better analysis of the points that need to be developed during the photovoltaic panel production stages.Öğe Control of Femtosecond Filamentation by Revivals of Nonadiabatic Molecular Alignment(IEEE, 2017) Kaya, Necati; Kaya, Gamze; Boran, Yakup; Kolomenskii, Alexandre A.; Amani, Mahmood; Schuessler, Hans A.[Anstract Not Available]Öğe Design of a New Ultra-sensitive Methane Sensor Based On Optical Approaches that Utilize Laser Diodes(Old City Publishing, 2021) Keskin, Alpgiray; Kaya, Necati; Kaya, GamzeWe design a new ultra-sensitive optical methane sensor by combining such optical approaches as appropriate use of absorption bands of methane by HITRAN database in the near-infrared (NIR) region, effective absorption path length in circular multi-pass optical cell, a wavelength modulation, and noise suppression with dual beam configuration. The design offers a compact and portable optical sensor for methane gas measurements in real time and high sensitivity. In the design, one can select different laser diode source to expand the selectivity labels for the interest many other trace gases. This is inexpensive and simpler experimental design without complexity of laser frequency locking and phase stabilization. It can find wide applications in many fields such as physical, environmental, and atmospheric research as well as physics, analytical chemistry, biology, medical diagnosis and process technology.Öğe Diffractive multifocal lenses by computer-generated holograms(SPIE (Society of Photo-optical Instrumentation Engineers), 2021) Kaya, Necati; Kaya, Gamze; Strohaber, James; Zhou, Junfeng; Kolomenskii, Alexandre A.; Schuessler, Hans A.The dynamics of rotational wave packets of laser-aligned linear molecules were studied with femtosecond laser-driven strong-field ionization (SFI). The dynamics were observed as a function of the delay between a femtosecond probe pulse and a linearly polarized aligning pump pulse. The induced nonadiabatic molecular alignment was directly monitored by the total SFI yield. The measured revival signatures were compared to the calculated degree of molecular alignment taking into account the effects of electronic structure and symmetry of the molecules. By fitting the calculated alignment parameter to the measured experimental data, we also determined the molecular rotational constants of N2, CO, O2, and C2H2 gas molecules.Öğe Diffractive multifocal lenses by computer-generated holograms(SPIE, 2021) Kaya, Necati; Kaya, Gamze; Strohaber, James; Zhou, Junfeng; Kolomenskii, Alexandre A.; Schuessler, Hans A.Diffractive lenses are optical elements commonly used in many applications owing to their simple and compact design. A multifocal diffractive lens enables the simultaneous focusing of an incident laser beam on several positions along the optical axis. The distances between the focal points and the energy densities in the foci can be changed by varying grating parameters, i.e., the modulation depth and the grating period. This requires grating structures that have to be fabricated for each targeted optical arrangement. Even though some methods for designing diffractive lenses with variable focal positions are available, they do not provide real-time control over the energy distribution and focal locations of the foci. We aimed to develop coaxial or multiaxial multifocus diffractive lenses with computer-generated holograms. The focal distances and energy densities in the foci can be dynamically controlled by programmable holographic codes. The generated holographic lenses can be used for imaging with dynamic repositioning of created images fast and easily. Such a holographic diffractive lens can withstand a highly intense laser radiation, so it can be used in nonlinear optics experiments and can be employed for high harmonic generation, pump-probe experiments, optical tweezers, filamentation, and other applications. © 2021 Society of Photo-Optical Instrumentation Engineers (SPIE).Öğe Dynamic Control of Airy Beams Using Real-Time Phase-Amplitude Encoding on a Spatial Light Modulator(Mdpi, 2024) Keskin, Alpgiray; Kaya, Gamze; Kaya, Necati; Strohaber, James; Kolomenskii, Alexandre A.; Schuessler, Hans A.Airy beams showing curved paths have found extensive applications in fields such as optical trapping, biomedical analysis, and material processing. Despite their utility, dynamic control of Airy beams poses a significant challenge. This work investigates the experimental realization of dynamic steering of Airy beams by utilizing computer-generated holograms with phase-amplitude encoding on a phase-only spatial light modulator (SLM). We successfully generated and controlled Airy beams by imposing dynamic phase masks that manipulated both the phase and amplitude of the field, which sets our approach apart from conventional methods with only phase manipulation. By directly encoding in situ such a hologram and transferring it to an SLM, we are able to control the initial position and rotational orientation of Airy beams without relying on mechanical movement or traditional optical setups involving lenses and apertures. Generating Airy beams in any initial position and rotational direction is anticipated to significantly impact applications such as optical trapping, optical communication, and biomedical imaging by providing a flexible platform for dynamic Airy beam manipulation.Öğe Energy and angular distributions of electrons from sodium atoms photo-ionized with femtosecond laser pulses(IOP Publishing Ltd, 2021) Boran, Y.; Hart, N.; Kaya, Necati; Zhou, J.; Kolomenskii, A. A.; Schuessler, H. A.We studied photoelectron angular distributions (PADs) and energy spectra of sodium atoms photo-ionized with intense short laser pulses in the near-infrared region. Energy spectra of photoelectrons due to multistep ionization of sodium atoms through intermediate levels 5p, 6p, 7p, and 4f were observed in above threshold ionization (ATI) at laser intensities of 2 × 1013 W cm−2 and 1 × 1013 W cm−2. The PADs from the 5p(4f) state for zero, first, second and third order ATI peaks were measured. We observed that for the two selected laser intensities the angular distribution of photoelectrons showed only slight variations. The PADs exhibit main lobes within ∼60◦ degrees from the laser polarization and additional lobes that become more pronounced with the increasing ATI peak number. Besides a general analytical representation of the observed angular dependences, the experimental PADs for each ATI peak were fitted with Legendre polynomials accounting for different ionization channels. The good agreement between the experimental data and fitting functions allowed to evaluate the contributions of the ionization channels to the observed ATI orders. The calculations of the photoelectron spectra by numerically solving the time-dependent Schrödinger equation in a single active electron approximation produced agreement with the experiment in the main features of the spectra, while differences in more subtle details were observed.Öğe In-situ measurement of aligning intensity and rotational temperature in field-free molecular alignment via white light generation(Elsevier GmbH, 2021) Kaya, Necati; Kaya, Gamze; Boran, Yakup; Kolomenski, Alexandre; Schuessler, Hans A.We determine the aligning intensity and rotational temperature in field-free molecular alignment measured via white light signal. Relying on temporal dependencies of the time-resolved alignment signature obtained via white-light generation by femtosecond laser pulses in N2 molecules, we derived the aligning pump intensity and rotational temperature using the occurrence times of the local alignment and anti-alignment around the half and full revivals. Results proved that the aligning intensity and rotational temperature can be obtained simultaneously by any two reverse local alignment extrema in the evolution of field-free molecular alignment.Öğe Preface to the special issue on The Sixth International Hydrogen Technologies Congress (IHTEC-2022)'(Pergamon-Elsevier Science Ltd, 2023) Koyuncu, Sermet; Kaya, Necati[Anstract Not Available]
