Design and modeling of a nanomechanical sensor using silicon photonic crystals

Chengkuo Lee, Rohit Radhakrishnan, Chii Chang Chen, Jing Li, Jayaraj Thillaigovindan, N. Balasubramanian

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


Conventionally a line defect in the photonic crystal (PhC) is used to create a waveguide for light propagation through the PhC. A PhC based filter is designed by introducing micro-cavities within the line defect so as to form the resonant bandgap structure for PhC. Such a PhC waveguide (PhCWG) filter shows sharp resonant peak in output wavelength spectrum. We proposed a suspended silicon bridge structure comprising this PhCWG filter structure. Since the output resonant wavelength is sensitive to the shape of air holes and defect length of the micro-cavity. Shift of the output resonant wavelength is observed for suspended PhCWG beam structure under particular force loading. In other words, the induced strain modifies the shape of air holes and the spacing among them. Such an effect leads to shift of resonant wavelength. Under optical detection limitation of 0.1 nm for resonant wavelength shift, the sensing capability of this nanomechanical sensor is derived as that vertical deformation is 20-25 nm at the center and the smallest strain is 0.005% for defect length. This innovative design conceptualizes a new application area for PhCs, i.e., the nanometer-scale physical sensors for strains and forces.

Original languageEnglish
Pages (from-to)839-846
Number of pages8
JournalJournal of Lightwave Technology
Issue number7
StatePublished - 1 Apr 2008


  • Microelectromechanical systems (MEMS)
  • Nano electromechanical systems (NEMS)
  • Nano mechanical sensor
  • Nano photonics
  • Photonic Crystals (PhCs)


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