Dual Wavelength Light Sources

Details

• Personal Author:
  Boos RT ; Defreeze RK ; Egan WD ; Elliott RA
• Description:
  This report describes work done to develop a tunable, room- temperature diode laser source for a remote coal mine methanometer. A detailed evaluation showed that a broad area ingaas/inp injection laser operating at approximately 1,650 nm could be suitable for a differential absorption light detection and ranging measurement of methane if the spectral bandwidth could be reduced by a factor of approximately 400. Consequently, an external grating cavity was designed and fabricated to reduce the bandwidth of the injection lasers. The optical design of an off-axis parabolic mirror grating cavity was developed using geometric optics to determine the physical parameters for the external cavity that would produce the desired spectral bandwidth of 0.2 Cm-1. Apart from a smaller than desired methane absorption coefficient, the device met all specifications. The low methane absorption coefficient was attributed to a larger than desired source linewidth, which was measured to be two to three times larger than the design value. The unsatisfactory methane absorption coefficient of the external cavity diode laser source significantly detracts from its suitability for use in an instrument to remotely measure methane in coal mines. [Description provided by NIOSH]
• Subjects:
  Coal Coal Mining Mining Occupational Health Safety
• Keywords:
  Coal Mining Infrared Radiation Injection Lasers Light Sources Methane Methanometer
• Series:
  Mining Publications
• Subseries:
  Open File Report
• Publisher:
  U.S. Department of the Interior, Bureau of Mines
• Document Type:
  Text
• Genre:
  Conference Publications ; Final Contract Report
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PRC - Pittsburgh Research Center
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-160
• NIOSHTIC Number:
  nn:10005149
• NTIS Accession Number:
  PB86-209483
• Citation:
  Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, Contract H0123031, 1985 Oct; :1-160
• Federal Fiscal Year:
  1986
• Performing Organization:
  Bethlehem Steel Corp
• Peer Reviewed:
  False
• Source Full Name:
  Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, Contract H0123031
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:e5e43ec469d2c8a205c4dfa3e6afdceb479e789ae48ea4567a39a63925eea3caaaa3cf9ac7236f9299dd3a749240d6b949eed30a08d8abaa29ba9ba416328e42
• Download URL:
  https://stacks.cdc.gov/view/cdc/206796/cdc_206796_DS1.pdf
• File Type:
  [PDF - 1.79 MB ]