Bio

Bio


Saeed Mohammadi got his B.Sc. and M.Sc. degrees in Microelectronics from Sharif University of Technology with focus on wireless devices. He then started his PhD studies at Georgia Institute of Technology, Atlanta, Georgia which resulted in a new, high performance, and low loss platform of micro/nano-electromechanical devices called phononic crystals-the acoustic counterpart of photonic crystals- with applications in wireless communications and sensing. He is currently a posdoctoral scholar at Stanford University working on a multimodality sensing platform combining electronics, MEMS, and photonics for early cancer detection. Saeed is a member of the National Organization for the Development of Exceptional Talents and a recipient of the bronze medal in the National Physics Olympiad in Iran. He is also a member of IEEE and OSA, and the winner of the best student paper award from the IEEE International Frequency Control Symposium. He is the author and co-author of more than 40 peer reviewed publications with more than 600 referrals.

Professional Education


  • Master of Engineering, Sharif Institute Of Technology (2003)
  • Doctor of Philosophy, Georgia Institute of Technology (2010)
  • Master of Science, Georgia Institute of Technology (2006)
  • Bachelor of Elec Engineering, Sharif Institute Of Technology (2001)

Stanford Advisors


Publications

Journal Articles


  • Electromechanical resonator based on electrostatically actuated graphene-doped PVP nanofibers NANOTECHNOLOGY Fardindoost, S., Mohammadi, S., zad, A. I., Sarvari, R., Panahi, S. P., Jokar, E. 2013; 24 (13)

    Abstract

    In this paper we present experimental results describing electrical readout of the mechanical vibratory response of graphene-doped fibers by employing electrical actuation. For a fiber resonator with an approximate radius of 850 nm and length of 100 μm, we observed a resonance frequency around 580 kHz with a quality factor (Q) of about 2511 in air at ambient conditions. Through the use of finite element simulations, we show that the reported frequency of resonance is relevant. We also show that the resonance frequency of the fiber resonators decreases as the bias potential is increased due to the electrostatic spring-softening effect.

    View details for DOI 10.1088/0957-4484/24/13/135201

    View details for Web of Science ID 000316208600003

    View details for PubMedID 23478541

  • Phononic bandgaps in silicon plate with metallic pillars ELECTRONICS LETTERS Pourabolghasem, R., Khelif, A., Eftekhar, A. A., Mohammadi, S., Adibi, A. 2012; 48 (18): 1147-U180
  • On chip complex signal processing devices using coupled phononic crystal slab resonators and waveguides (vol 1, 041903, 2011) AIP ADVANCES Mohammadi, S., Adibi, A. 2012; 2 (1)

    View details for DOI 10.1063/1.3694658

    View details for Web of Science ID 000302225400115

  • Simultaneous high-Q confinement and selective direct piezoelectric excitation of flexural and extensional lateral vibrations in a silicon phononic crystal slab resonator SENSORS AND ACTUATORS A-PHYSICAL Mohammadi, S., Eftekhar, A. A., Pourabolghasem, R., Adibi, A. 2011; 167 (2): 524-530
  • Acoustic confinement and waveguiding with a line-defect structure in phononic crystal slabs JOURNAL OF APPLIED PHYSICS Khelif, A., Mohammadi, S., Eftekhar, A. A., Adibi, A., Aoubiza, B. 2010; 108 (8)

    View details for DOI 10.1063/1.3500226

    View details for Web of Science ID 000283745100154

  • Simultaneous two-dimensional phononic and photonic band gaps in opto-mechanical crystal slabs OPTICS EXPRESS Mohammadi, S., Eftekhar, A. A., Khelif, A., Adibi, A. 2010; 18 (9): 9164-9172

    Abstract

    We demonstrate planar structures that can provide simultaneous two-dimensional phononic and photonic band gaps in opto-mechanical (or phoxonic) crystal slabs. Different phoxonic crystal (PxC) structures, composed of square, hexagonal (honeycomb), or triangular arrays of void cylindrical holes embedded in silicon (Si) slabs with a finite thickness, are investigated. Photonic band gap (PtBG) maps and the complete phononic band gap (PnBG) maps of PxC slabs with different radii of the holes and thicknesses of the slabs are calculated using a three-dimensional plane wave expansion code. Simultaneous phononic and photonic band gaps with band gap to midgap ratios of more than 10% are shown to be readily obtainable with practical geometries in both square and hexagonal lattices, but not for the triangular lattice.

    View details for Web of Science ID 000277082200047

    View details for PubMedID 20588763

  • Support Loss-free Micro/Nano-mechanical Resonators using Phononic Crystal Slab Waveguides 2010 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM (FCS) Mohammadi, S., Eftekhar, A. A., Adibi, A. 2010: 521-523
  • Support Loss Suppression in Micromechanical Resonators by the use of Phononic Band Gap Structures PHOTONIC AND PHONONIC CRYSTAL MATERIALS AND DEVICES X Mohammadi, S., Eftekhar, A. A., Khelif, A., Adibi, A. 2010; 7609

    View details for DOI 10.1117/12.849038

    View details for Web of Science ID 000283790200014

  • High-Q micromechanical resonators in a two-dimensional phononic crystal slab APPLIED PHYSICS LETTERS Mohammadi, S., Eftekhar, A. A., Hunt, W. D., Adibi, A. 2009; 94 (5)

    View details for DOI 10.1063/1.3078284

    View details for Web of Science ID 000263167000024

  • Evidence of large high frequency complete phononic band gaps in silicon phononic crystal plates APPLIED PHYSICS LETTERS Mohammadi, S., Eftekhar, A. A., Khelif, A., Hunt, W. D., Adibi, A. 2008; 92 (22)

    View details for DOI 10.1063/1.2939097

    View details for Web of Science ID 000256527900027

  • Demonstration of Large Complete Phononic Band Gaps and Waveguiding in High-Frequency Silicon Phononic Crystal Slabs 2008 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM, VOLS 1 AND 2 Mohammadi, S., Eftekhar, A. A., Hunt, W. D., Adibi, A. 2008: 768-772
  • Large Simultaneous Band Gaps for Photonic and Phononic Crystal Slabs 2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9 Mohammadi, S., Eftekhar, A. A., Adibi, A. 2008: 308-309
  • Complete phononic bandgaps and bandgap maps in two-dimensional silicon phononic crystal plates ELECTRONICS LETTERS Mohammadi, S., Eftekhar, A. A., Khelif, A., Moubchir, H., Westafer, R., Hunt, W. D., Adibi, A. 2007; 43 (16): 898-899
  • Complete band gaps in two-dimensional phononic crystal slabs PHYSICAL REVIEW E Khelif, A., Aoubiza, B., Mohammadi, S., Adibi, A., Laude, V. 2006; 74 (4)

    Abstract

    The propagation of acoustic waves in a phononic crystal slab consisting of piezoelectric inclusions placed periodically in an isotropic host material is analyzed. Numerical examples are obtained for a square lattice of quartz cylinders embedded in an epoxy matrix. It is found that several complete band gaps with a variable bandwidth exist for elastic waves of any polarization and incidence. In addition to the filling fraction, it is found that a key parameter for the existence and the width of these complete band gaps is the ratio of the slab thickness, d, to the lattice period, a. Especially, we have explored how these absolute band gaps close up as the parameter d/a increases. Significantly, it is observed that the band gaps of a phononic crystal slab are distinct from those of bulk acoustic waves propagating in the plane of an infinite two-dimensional phononic crystal with the same composition. The band gaps of the slab are strongly affected by the presence of cutoff frequency modes that cannot be excited in infinite media.

    View details for DOI 10.1103/PhysRevE.74.046610

    View details for Web of Science ID 000241723000078

    View details for PubMedID 17155195

  • Compact wavelength demultiplexing using focusing negative index photonic crystal superprisms OPTICS EXPRESS Momeni, B., Huang, J. D., Soltani, M., Askari, M., Mohammadi, S., Rakhshandehroo, M., Adibi, A. 2006; 14 (6): 2413-2422

    Abstract

    Here, we demonstrate a compact photonic crystal wavelength demultiplexing device based on a diffraction compensation scheme with two orders of magnitude performance improvement over the conventional superprism structures reported to date. We show that the main problems of the conventional superprism-based wavelength demultiplexing devices can be overcome by combining the superprism effect with two other main properties of photonic crystals, i.e., negative diffraction and negative refraction. Here, a 4-channel optical demultiplexer with a channel spacing of 8 nm and cross-talk level of better than -6.5 dB is experimentally demonstrated using a 4500 microm(2) photonic crystal region.

    View details for Web of Science ID 000236202800045

    View details for PubMedID 19503580

  • Hypersonic band gaps in two-dimensional piezoelectric phononic crystal slabs 2005 IEEE ULTRASONICS SYMPOSIUM, VOLS 1-4 Khelif, A., Aoubiza, B., Mohyammadi, S., Adibi, A., Laude, V. 2005: 65-68

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