A5079088653- Photonic and Optical Devices
- Photorefractive and Nonlinear Optics
- Advanced Fiber Laser Technologies
- Liquid Crystal Research Advancements
- Orbital Angular Momentum in Optics
- Synthesis and properties of polymers
- Terahertz technology and applications
- Near-Field Optical Microscopy
- Photochromic and Fluorescence Chemistry
- Photonic Crystals and Applications
- Nonlinear Optical Materials Research
- Semiconductor Quantum Structures and Devices
- Optical Coatings and Gratings
- Superconducting and THz Device Technology
- Microfluidic and Bio-sensing Technologies
- Optical and Acousto-Optic Technologies
- Laser-Matter Interactions and Applications
- Nonlinear Photonic Systems
- Nonlinear Optical Materials Studies
- Carbon Nanotubes in Composites
- 2D Materials and Applications
- Solid State Laser Technologies
- Thermal Radiation and Cooling Technologies
- Perovskite Materials and Applications
- Silicon Nanostructures and Photoluminescence
Texas A&M University at Qatar
2016-2023
Warsaw University of Technology
2011-2021
Texas A&M University
2018
Abstract Generation of coherent light with desirable amplitude and phase profiles throughout the optical spectrum is a key issue in technologies. Nonlinear wavefront shaping offers an exceptional way to achieve this goal by converting incident beam into (or beams) different frequency spatially modulated phase. The realization such conversion processes critically depends on matching velocities interacting waves, for which nonlinear photonic crystals (NPCs) quadratic nonlinearity have shown...
Abstract Nonlinear photonic crystals (NPCs) with spatially modulated second‐order nonlinear coefficients are indispensable in optics and modern photonics. To access full degrees of freedom the generation control coherent light at new frequencies, three dimensional (3D) NPCs have been recently fabricated employing femtosecond laser writing technique ferroelectric crystals. However, interaction efficiencies 3D so far rather low, which has a major barrier to further development. Here,...
We report Raman spectra measurements on a MoS2 monolayer supported SiO2 as function of temperature. Unlike in previous studies, the positions two main modes, E2g1 and A1g exhibited nonlinear temperature dependence. Temperature dependence phonon shifts widths is explained by optical decay process into acoustic phonons. On basis measurements, local change under laser heating power at different global temperatures derived. Obtained results contribute to our understanding thermal properties...
We report the development of microscopic size gradient index vortex masks using modified stack-and-draw technique. The mask has a form flat surface all-glass plate. Its functionality is determined by an internal nanostructure composed two types soft glass nanorods. generation optical vortices with charges 1 and 2 demonstrated.
We discuss thin optical structures that allow chromatic aberrations to be avoided in the THz domain. The paper contains theoretical considerations, computer modeling and experimental evaluation of high order kinoform diffractive elements range. According obtained results application kinoforms enables broadband operation
We study optical performance of a vortex beam converter comprising nanostructured gradient index mask, compact microlens and an fiber. The generates high quality focused from the input Gaussian without support any additional external elements. Integration lens allows control size position focus beams, while at same time maintaining their quality. This confirms that micro-optical components can be used sequentially to form complex systems maintain full compatibility with fiber optics. Our...
Abstract This paper reports novel photoresponsive, processable poly(esterimide)s functionalized with the azobenzene and tricyanovinylene groups. Post prepolymerization strategies were utilized for preparation of new photochromic polymers imide rings. The postpolymerization method azopolymer synthesis included a functionalization precursor poly(esterimide) containing dialkylaminophenyl groups diazonium salt aniline. was obtained from synthesized 2,2′[ N...
The photoinduced birefringence resulting from trans–cis–trans isomerizations has been measured in a thin film of azobenzene-functionalized poly(esterimide) at three excitation wavelengths. wavelengths 388 and 420 nm have located exactly opposite sides the trans azobenzene absorption band. A third irradiation wavelength was shifted to 438 nm. Distinct saturation levels growth dynamics observed under 388- 420-nm illumination, while very similar characteristics were recorded Differences...
Thin films of multi-walled carbon nanotubes forming random networks were produced by vacuum filtration method, and their broadband electromagnetic radiation transmittance spectra are presented. Thickness the nanotube was between 100 nm 1 μm, transmission properties demonstrated for wavelength range from 300 to 400 μm. It is observed that an increasing function a wavelength, thickest it almost saturates above μm wavelength. To explain experimental results in ultraviolet–near infrared range,...
We present an experimental study on the Čerenkov second harmonic emission in a novel sunflower spiral array of ferroelectric domains LiNbO3 crystal. The patterns offer diffusive, circularly symmetric distribution reciprocal lattice vectors, thereby enabling enhanced beam broad spectral range. Instead traditional electric field poling, are fabricated here by using our pioneering method domain engineering with ultrafast light. This all-optical gives access to high quality structures short...
Ultra-short high-intensity light pulses were utilized to induce the optical birefringence in a polyimide material possessing azo-dye covalently bonded main chain. The obtained results showed that two-photon absorption process was involved creation of sample which, best our knowledge, not previously reported for materials. growths and decays examined as functions pulse intensities. No damage during illumination detected wide range powers applied. High level order 0.005 measured.
We introduce a custom-cut periodically poled ferroelectric crystal for the phase matching of multistep cascading frequency conversion processes. Our approach involves combination collinear second harmonic generation and transverse sum mixing via total internal reflection fundamental beams. As proof concept we demonstrate multiple with an enhanced fourth signal in one-dimensional LiNbO3 crystal.
We present an indirect, non-destructive optical method for domain statistic characterization in disordered nonlinear crystals having homogeneous refractive index and spatially random distribution of ferroelectric domains. This relies on the analysis wave-dependent spatial second harmonic, plane perpendicular to axis combination with numerical simulations. apply this technique two different media, Calcium Barium Niobate Strontium Niobate, drastically statistical distributions
Characterization of the Time Domain Spectroscopy goniometric setup in THz range is reported. During construction TDS many elements need proper adjustment. Additionally, steering and data processing systems should be optimized. Test phase diffraction grating with a saw blade profile was measured setup. The performance system can optimized on basis experimental comparison theoretical results. Full Text: PDF References Y.-S. Lee, Principles Terahertz Science Technology(Springer, 2008). T. Yasui...
Based on the reflectance spectra for radiation wavelength from about 380 nm to 1.8 µm, optical interference effects in vertically aligned multiwalled carbon nanotubes films are studied.We performed measurements two complementary polarization states of incoming (s-and p-polarization) arrays sparse enough be possible observe.By performing different wavelengths and incidence angles, we mapped evolution maxima/minima signal.The results this novel approach indicate that polarized perpendicularly...