Researcher:
Azeem, Farhan

Profile Picture
ORCID

Job Title

Master Student

First Name

Farhan

Last Name

Azeem

Name

Name Variants

Azeem, Farhan

Email Address

Birth Date

Filters

2015 - 201922020 - 20241

Advanced Search

Filter by

Settings

Researcher Of Publications: search.filters.isAuthorOfPublication.6d9c5a4f-b70c-45eb-bd1d-81ef9dc2f775

Search Results

Now showing 1 - 3 of 3
  • Placeholder
    PublicationMetadata only
    Optical whispering gallery mode resonators: analysing thermo-optic tuning in a silicon sphere
    (Taylor and Francis Asia Pacific, 2024) Khan, Haseeb Ahmad; Ma, Li; Khan, Adnan Daud; Azeem, Farhan; Chaudhry, Muhammad Rehan; Anwar, Muhammad Sohail; Graduate School of Sciences and Engineering
    In this work, we discuss and experimentally investigate the whispering gallery modes (WGMs) in a 500 μm radius silicon sphere. We begin by reviewing the basics of WGM resonators, followed by simulations and experimental results obtained with the aforementioned silicon spherical WGM resonator. The recorded WGM signatures in the transmission and scattering spectra excited, in the near-infrared (near-IR) region, agree well with the simulations. Thermo-optic tuning of these WGMs is achieved by introducing a pump laser in the violet-blue region. Red-shifts in wavelength are observed, which increase with the increase in the pump power. A shift of 0.63 nm is observed at a pump power of 6.32 mW. We also study switching by analysing the transient response of the WGM spectra. The measured WGMs exhibit high quality factors ((Formula presented.)), which along with the aforesaid tunability, demonstrates the potential of spherical silicon resonator as a platform for photonic applications, e.g. sensing and communication. In summary, this work contributes towards the understanding of the fundamental physics of WGMs and provides insights into silicon WGM resonators.
  • Placeholder
    PublicationMetadata only
    Far-infrared elastic scattering proposal for the Avogadro Project's silicon spheres
    (Elsevier, 2018) Department of Physics; N/A; N/A; N/A; N/A; N/A; N/A; Department of Physics; Serpengüzel, Ali; Humayun, Muhammad Hamza; Khan, Imran; Azeem, Farhan; Chaudhry, Muhammad Rehan; Gökay, Ulaş Sabahattin; Murib, Mohammed Sharif; Faculty Member; Researcher; Master Student; Researcher; Researcher; PhD Student; Researcher; College of Sciences; College of Sciences; Graduate School of Sciences and Engineering; College of Sciences; College of Sciences; Graduate School of Sciences and Engineering; College of Sciences; 27855; N/A; N/A; N/A; N/A; N/A; N/A
    Avogadro constant determines the number of particles in one mole of a substance, thus relating the molar mass of the substance to the mass of this substance. Avogadro constant is related to Systeme Internationale base units by defining the very concept of chemical quantity. Revisions of the base units created a need to redefine the Avogadro constant, where a collaborative work called the Avogadro Project is established to employ optical interferometry to measure the diameter of high quality 100 mm silicon spheres. We propose far-infrared spectroscopy for determining the Avogadro constant by using elastic scattering from the 100 mm Avogadro Project silicon spheres. Similar spectroscopic methods are already in use in the near-infrared, relating whispering gallery modes of the 1 mm silicon spheres to the diameter of the spheres. We present numerical simulations in the far-infrared and the near-infrared, as well as spatially scaled down elastic scattering measurements in the near-infrared. These numerical and experimental results show that, the diameter measurements of 100 mm single crystal silicon spheres with elastic scattering in the far-infrared can be considered as an alternative to optical interferometry.
  • Placeholder
    PublicationMetadata only
    Silicon microspheres in metrology
    (Electromagnetics Academy, 2015) N/A; N/A; N/A; N/A; N/A; Department of Physics; Department of Physics; Humayun, Muhammad Hamza; Azeem, Farhan; Khan, Imran; Gökay, Ulaş Sabahattin; Serpengüzel, Ali; Master Student; Master Student; Master Student; PhD Student; Faculty Member; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Sciences; N/A; N/A; N/A; N/A; 27855
    The Système International unit of mass is the kilogram. The present definition of the kg is based on a prototype dating back to 1880s. New approaches to define the unit of mass are being investigated. Avogadro Project uses 10 cm diameter single crystal silicon spheres. The technique commonly observed to measure the radius of the silicon sphere is optical interferometry. Here, we propose an alternate method of measuring the diameter of the single crystal silicon sphere using near-infrared spectroscopy. We demonstrate our approach by numerically simulating the electromagnetic coupling of a silicon microdisk of radius 5 µm to an optical waveguide of width 0.5 µm, thereby approximating the coupling of a microsphere to a rectangular optical waveguide. It might be possible to have a precise technique for determining the radius of the sphere, which can be used for the definition of the kilogram.