Fresnel Sapphire Split-Prism Spectrometer for Engine Emissions Diagnostics

EPA Contract Number: 68D01038
Title: Fresnel Sapphire Split-Prism Spectrometer for Engine Emissions Diagnostics
Investigators: Rentz, Julia
Small Business: OPTRA Inc.
EPA Contact: Manager, SBIR Program
Phase: I
Project Period: April 1, 2001 through September 1, 2001
Project Amount: $69,594
RFA: Small Business Innovation Research (SBIR) - Phase I (2001) RFA Text |  Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , SBIR - Monitoring , Small Business Innovation Research (SBIR)


OPTRA, Inc., is proposing a low-resolution ( 15 nm) Fresnel sapphire split-prism spectrometer specifically tailored to the identification of molecular species present in the emissions from an engine source. The proposed approach will examine the 3-5.5 µm spectral region, allowing for the extraction of concentration information of CO2, CO, NO, HCs, and particulate matter. Sapphire was chosen because of its very high dispersion in this spectral region. The split-prism configuration is used to counter the effects of the birefringence of sapphire, which otherwise would produce separate overlapping spectra for the s and p polarizations. The Fresnel realization of the prism allows for a more compact system and potentially higher throughput. The spectral bandwidth for each detector channel is selected to maximize signal-to-noise while retaining adequate spectral resolution for the identification of molecular species. A room-temperature amorphous silicon microbolometer array will be used as the detector, allowing coverage of the full 3-5.5 µm spectral region. Using reflective optics and containing no moving parts, this spectrometer will be compact, rugged, and ideally suited for its purpose.

Supplemental Keywords:

small business, SBIR, engine emissions, split-prism spectrometer, sapphire, optics, engineering, chemistry, EPA, CO2, CO, NO, hydrocarbons, particulate matter, PM, air pollution., RFA, Scientific Discipline, Air, particulate matter, air toxics, Environmental Chemistry, Chemistry, Civil/Environmental Engineering, mobile sources, Engineering, Engineering, Chemistry, & Physics, Environmental Engineering, monitoring, Nitrogen Oxides, particulates, hydrocarbon, spectrometer, fresnel sapphire, engines, air pollution, split prism , emissions, diagnostics, carbon dioxide, carbon monoxide, hydrocarbons, split-prism spectrometer

Progress and Final Reports:

  • Final Report