Jump to content, Georgia Institute of Technology, College of Engineering, School of Electrical and Computer Engineering (ECE), ECE Research, ECE Research Centers, GT-Bionics
College of Engineering
Search | Contact ECE | Feedback | BuzzPort
GT Home > COE Home > ECE Home > Research > Labs > Optics Laboratory
Georgia Tech
Georgia Tech   Optics Laboratory
line

Research Areas

Areas of research of the Optics Laboratory include the following:

  • Optical interconnects
  • Photonic crystal devices
  • Diffractive optics
  • Waveguide optics
  • Optical measurements and instrumentation
  • Fiber grating variable optical attenuators
  • Fiber grating tuners
  • Fiber and fiber device characterization
  • Semiconductor quantum devices
  • Intersubband photodetectors and lasers
  • Optical methods of chemical and biological sensing

Recent Projects

  • Multi-Beam-Interference Lithography
    Multi-beam-interference lithography is a technique in which mulitple beams of coherent light interfere in space producing a periodic interference pattern. These periodic interference patterns along with standard lithographic processes allow for the fabrication of a multitude of micro- and nano-scale periodic structures. The animated figures below show the instantaneous magnitude of the electric field for three different configurations of three-beam interference, differing only in the polarization of each interfering beam. The time-average intensity distribution of all three configurations exhibits p6m plane group symmetry. This intensity distribution can be used in a lithographic process to define hexagonal-lattice structures.

    Interference pattern resulting in time-average intensity maxima at lattice points.
    MBIL pattern 1

    Interference pattern resulting in time-average intensity minima at lattice points.
    MBIL pattern 2

    Interference pattern resulting in time-average intensity maxima at lattice points.
    MBIL pattern 3

    For more information on MBIL, see:

    J. L. Stay and T. K. Gaylord, "Contrast in four-beam-interference lithography," Opt. Lett., vol. 33, pp. 1434-1436, July 1, 2008.

    and

    J. L. Stay and T. K. Gaylord, "Three-beam-interference lithography: contrast and crystallography," Appl. Opt., vol. 47, pp. 3221-3230, June 20, 2008.

  • Microinterferometric Optical Phase Tomography
    Microinterferometric Optical Phase Tomography (MIOPT) is a method for determining the cross-sectional refractive index profile of optical fibers. The method combines microscopy-based fringe-field interferometry with parallel projection-based computed tomography. The method is especially well suited for measuring the small, asymmetric refractive-index differences in the cross sectional profiles of long-period fiber gratings (LPFGs). The figure below shows a typical transverse cross-sectional refractive-index profile of the exposed region of a CO2-laser-induced LPFG.
    MIOPT results
    For more information on the MIOPT method, see:

    B. L. Bachim and T. K. Gaylord, "Microinterferometric optical phase tomography measuring small, asymmetric refractive-index differences in the profiles of optical fibers and fiber devices," Appl. Opt., vol. 44, pp. 316-27, Jan. 20, 2005.

    and

    B. L. Bachim, T. K. Gaylord, and S. C. Mettler, "Refractive-index profiling of azimuthally asymmetric optical fibers by microinterferometric optical phase tomography," Opt. Lett., vol. 30, pp. 1126-8, May 25, 2005.

  • Two-Waveplate Compensator Technique
    The two-waveplate compensator technique is an optical retardation measurement technique. The technique is capable of making single-point retardation measurements using bulk optics and full-field retardation measurements using a polarization microscope. The figure below shows the retardation produced by the exposed region of a CO2-laser-induced LPFG.
    TWC results
    For more information on the TWC technique, see:

    C. C. Montarou and T. K. Gaylord, "Two-wave-plate compensator method for single-point retardation measurements," Appl. Opt., vol. 43, pp. 6580-6595, Dec. 20, 2004.

    and

    C. C. Montarou, T. K. Gaylord, B. L. Bachim, A. I. Dachevski, and A. Agarwal, "Two-wave-plate compensator method for full-field retardation measurements," Appl. Opt., vol. 45, pp. 271-80, Jan. 10, 2006.

Facilities

The Optics Laboratory, in conjuntion with the extensive resources of the Microelectronics Research Center offers state-of-the-art facilities that support all aspects of optics research, including:

  • Mask-making
  • Photo- and electron-beam lithography
  • Thin-film deposition
  • Reactive-ion etching
  • Optical testing
  • Ellipsometry

Custom-constructed facilites include:

  • Ultraviolet exposure facility for fabrication of volume and surface-relief gratings
  • Carbon-dioxide laser configuration for fabrication of long-period fiber gratings
  • High-resolution Fourier Transform InfraRed (FTIR) spectrometer
  • Polarization microscopy and differential interferece microscopy combined with spectrophotometry
line

Last revised on May 5, 2011