Nor Roshidah Yusof
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Nor Roshidah Yusof
Official Name
Nor Roshidah, Yusof
Alternative Name
Roshidah, N.
Yusof, Nor Roshidah
Yusof, N. R.
Yusof, Roshidah
Main Affiliation
Scopus Author ID
56023921300
Researcher ID
ITT-8107-2023

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  • Publication
    Generation Orbital Angular Momentum Modes Using Metasurfaces
    ( 2023-10-06)
    NHuda S.
    ;
    Norshamsuri Ali @ Hasim
    ;
    Amphawan A.
    ;
    Nor Roshidah Yusof
    ;
    Rosdisham Endut
    ;
    Nor Azura Malini Ahmad Hambali
    ;
    Mohd Najib Mohd Yasin
    ;
    Syed Alwee Aljunid Syed Junid
    The purpose of this study is to investigate how numerous orbital angular momentum (OAM) modes may be produced by mixing acoustic plane beams with different metasurfaces. This study proposes a novel metasurface that may be simulated in order to generate OAM beams. Multi-beam and multi-mode terahertz wave incidence are produced utilizing vortex modes in the beams. The study of suitable OAM superpositions of waveguide eigenmodes is done using COMSOL Multiphysic, followed by a description of the software's usage and examples of challenges involved. With the existence of these studies, we can also prove that the mode can be produced completely with the results that have been studied. Based on the results obtained, an objective was achieved, which is to design the feature of the vortex beam modes. These results include the construction of a multi-functional vortex beam based on a theoretical model of phase gradient distribution. Also, by using metasurface mimics to specify a periodic structure specified by the user from the built-in unit cell, and the beam was attenuated and split into two paths inside the thin layer. Finally, the simulation process between 2D and 3D is very significant because the mesh and geometry in a design are very different, but generating a beam using COMSOL already has a specific module, namely the wave optic module, which can be used to predict the beam modes.
  • Publication
    The influence of crystal orientation variation towards the modal phase matching condition in Lithium Niobate on insulator waveguide
    ( 2022-12)
    Nor Roshidah Yusof
    ;
    Norshamsuri Ali @ Hasim
    ;
    Piotr Kolenderski
    We systematically demonstrate the influence of crystal orientation towards the phase matching condition in Lithium Niobate on insulator waveguide structure. The phase matching condition is one of the important elements that required prior to the development of ultracompact photonic integrated circuit. This is achieved as the effective refractive indices of fundamental mode, TE00 at pump wavelength overlapped with the second order mode, TE20 of second harmonic wavelength. With a proper selection of crystal orientation, the perfect phase matching condition is achievable over a broader telecommunication wavelength, hence, improve the efficiency of the device. In this work, we examine the phase matching interaction over the x-, y- and z- cut LNOI crystal structure. From the numerical analysis, the significant variation of phase matching width over crystal orientation is demonstrated with x-cut LNOI shows a strong ability to achieve the modal phase matching at narrower width, allowing the realization of ultracompact waveguide fabrication. Interestingly, z-cut LNOI, offers a broader range of phase matching wavelength tunability which beneficial for the development of optical modulator. Eventually, the y-cut LNOI suit for the fabrication of the wavelength-independent optical devices such as surface acoustic waveguide.
  • Publication
    Digital fringe projection for hand surface coordinate variation analysis caused by osteoarthritis
    ( 2017)
    Wan Mokhdzani Wan Nor Haimi
    ;
    Cheek Hau Tan
    ;
    Vithyacharan Retnasamy
    ;
    Rajendaran Vairavan
    ;
    Muhammad Hafiz Ab Aziz
    ;
    Zaliman Sauli
    ;
    Nor Roshidah Yusof
    ;
    Nor Azura Malini Ahmad Hambali
    ;
    Ahmad Syahir Ahmad Bakhit
    Hand osteoarthritis is one of the most common forms of arthritis which impact millions of people worldwide. The disabling problem occurs when the protective cartilage on the boundaries of bones wear off over time. Currently, in order to identify hand osteoarthritis, special instruments namely X-ray scanning and MRI are used for the detection but it also has its limitations such as radiation exposure and can be quite costly. In this work, an optical metrology system based on digital fringe projection which comprises of an LCD projector, CCD camera and a personal computer has been developed to anticipate abnormal growth or deformation on the joints of the hand which are common symptoms of osteoarthritis. The main concept of this optical metrology system is to apply structured light as imaging source for surface change detection. The imaging source utilizes fringe patterns generated by C++ programming and is shifted by 3 phase shifts based on the 3 steps 2 shifts method. Phase wrapping technique and analysis were applied in order to detect the deformation of live subjects. The result has demonstrated a successful method of hand deformation detection based on the pixel tracking differences of a normal and deformed state.
  • Publication
    Phase matching in microstructured lithium niobate on insulator waveguides
    ( 2023)
    Nor Roshidah Yusof
    ;
    Norshamsuri Ali @ Hasim
    ;
    Piotr Kolenderski
    ;
    Karolina SÅ‚owik
    ;
    Rosdisham Bin Endut
    ;
    Syed Alwee Aljunid Syed Junid
    The recent development of the Lithium Niobate on Insulator (LNOI) fabrication process has opened a bright future for integrating ultra-compact photonic circuits. Due to its excellent nonlinear properties, as a waveguide material, Lithium Niobate supports nonlinear optical processes including efficient sum frequency generation and second harmonic generation. To enhance these effects, precise control of mode confinement and modal phase matching is required. In this work, we engineer an LNOI waveguide to match the effective refractive indices of the fundamental mode, TE00 at the fundamental wavelength and second-order mode, TE20 at the second harmonic wavelength. As waveguide geometry plays an essential role, optimization of waveguide parameters is crucial for the design of high-performance, feasible devices. Here, we numerically engineer and characterize the influence of rib waveguide geometry parameters including etching depth, D , width, W and sidewall angle, θ on the phase matching condition. We find that the waveguide phase matching condition is most susceptible to variations in the sidewall angle. For the optimized parameter values of {D,θ}={450nm,10o} , the phase-matching wavelength tunability is achieved through the waveguide width control.