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Multi-frequency chirped laser pulses for improved range resolution

This research examines the theoretical and experimental aspects of multiple laser line linear frequency chirped signal processing for improving range resolution. Calculations established that a factor of two improvement in range resolution could be achievable with two chirped frequencies. Additional improvement is found for a third and fourth frequency, as well. The goals for this project include:

  • Complete calculations for chirped multi-frequency laser pulses and heterodyne detection and processing of field amplitudes. Use the results to specify experimental components.
  • Design and conduct experiments with two detuned lasers.
Aperture synthesis technologies

Coherent imaging research experiment using multiple apertures. The goals for this project include:

  • Using phase shift technique, compute image plane phase field. Study statistical properties of computed phase field and investigate phase unwrapping techniques. Synthesize image from sub-aperture pupil plane fields measured by Phase Stepping Interferometry technique. Methods are developed to mitigate image speckle.
  • Examination of alternate sparse aperture phase retrieval methods.


  • Oblique angle of incidence penetration and scattering of light from a canopy.
  • Extensive Monte Carlo calculations to understand the phenomenology.
  • Experiments on local canopy gap fractions.
  • Analysis of data and comparison with MC calculations.
Non-mechanical beamsteering for LIDAR applications

A large aperture (20 mm) Faraday rotator device is being used as an R/T switch for a LIDAR module. This obviates the need for a quarter-wave plate and enables linear polarization to be transmitted. The project will experimentally verify new concept of focal plane shifter beam steering. Different beam steerers will be examined including: Liquid crystal (LC) based beam steering devices and Electro-optic (EO) beam steering devices.  The goals for this project include:

  • Gaussian beam characterization using a camera and parabolic mirrors for off-axis beams.
  • Understanding the polarization issues in the LC beamsteering by theoretical modeling. Integration of a beam steering subsystem (LC SLM or Risley prisms) to study component interactions with Faraday rotator and evaluated overall performance for T/R setup.
  • Design and test beam steering with LC devices.
Single holographic aperture demonstration

A synthetic aperture reconstruction of a moving transmitter/receiver system to improve the resolution. The goal of this project is:

  • Calculations of effects of platform vibrations and laser pulse timing jitter. Experimental design and construction based on simulations.
Non-uniform sparse aperture and sub-aperture pupil apodization

A multiple aperture project designed to improve image contrast. The goals for this project include:

  • A theoretical examination of sub apertures with different radii and different opacity, starting with Golay topologies.
  • Simulations to drive the MTF to higher frequencies with improved image contrast.
Laser beam propagation and interaction with simulated targets

Research on the experiments and design concepts for simulating the speckle field associated with laser propagation through the atmosphere and scattered from a scattering target.  The goals for this project include:

  • Experiments and design concepts for simulating the speckle field associated with laser propagation through the atmosphere and scattered from a scattering target.
  • Theoretical simulations on partially coherent light fields to anchor the experimental results and modeling approach.
Testbed design and implementation

LOCI researchers in cooperation with AFRL researchers are designing and building a multi-aperture testbed with visible and NIR capabilities to examine the optical components and post-processing approaches to multi-aperture imaging.

The goals for this project include:

Lidar and Optical Communications Institute

Fitz Hall
300 College Park
Dayton, Ohio 45469 - 2950