Schematic diagram of a system for analyzing polarized light back-scattered from a sample

Systems and Methods for Analyzing Polarized Light

The US Army seeks a partner to license and commercialize methods for analyzing polarized light back-scattered from a sample.

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Technology Description

Background and Technology:

Measurements of back-scattered light are of interest for remote sensing techniques like light detection and ranging (LIDAR), and for providing information about the size and distribution of particles of interest, such as biological materials. However, analyzing particle systems with light typically requires that two measurements be taken at different times, making real-time characterization of particles difficult or inaccurate.

The US Army has developed a system and method for the light detection of biological threat materials such as anthrax. While the method was developed to analyze aerosol particles, it can be used to analyze bulk samples as well. The magnitude of the method’s signal depends on the monodispersity of the sample and its position depends on the size of the sample’s components. It is designed to measure the size of individual spores composing an aerosol or a sample and can be used in quality control of samples, or to make the cut-off point in growth of individual cells composing a biological sample.

The method allows for the rapid characterization of aerosol particles based on analyzing the back-scattering of the polarized light reflected from the materials being examined. The system employs an optical beamsplitter, a polarization separator, and an array of light detectors. Using an inexpensive laser source, the beamsplitter directs a portion of the incident ray to a sample and also receives a portion of the back-scattered light. The polarization separator is then used to divide the reflected back-scattered light into both transverse-electric (TE) and a transverse-magnetic (TM) components at same time, eliminating the need for separate measurements. The system can be configured to recognize when certain types and sizes of aerosol particles are detected in a sample, providing a relatively low cost, real-time “front-end” to a comprehensive aerosol particle detection system.

The invention could also be used to support quality control in clean room operations, food safety, targeted applications such as the paints industry (e.g., measuring the effective use of titanium dioxide in paints), and detection of mold and other harmful aerosol spores.


  • Provides light detection and rapid characterization of aerosol and non-aerosol particles.
  • Ability to capture transverse electric and transverse magnetic information simultaneously.
  • Low cost design can be tailored for a number of different detection and quality control applications

The Opportunity: 

  • Issued US Patent 7,440,102 available for license
  • Potential for collaboration with US Army scientists and laboratory
  • A prototype was previously assembled to establish laboratory proof of principle

For more information, contact:
Brian Metzger, PhD (406) 994-7782,

Licensing Instructions:

In order to apply for license to federally owned technologies, regulations require that specific information be provided regarding your company and plans for commercialization. This information will be incorporated in a license agreement which will be provided for your review prior to signature. All provided information will be considered proprietary and held confidential.

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