VTechWorks staff will be away for the Thanksgiving holiday beginning at noon on Wednesday, November 27, through Friday, November 29. We will resume normal operations on Monday, December 2. Thank you for your patience.

Fiber & ElectroOptics Research Center (FEORC)

Permanent URI for this community

https://hdl.handle.net/10919/25862

Browse

Browsing Fiber & ElectroOptics Research Center (FEORC) by Author "Aggarwal, I. D."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Characterization And Modeling Of Drift Noise in Fourier Transform Spectroscopy: Implications For Signal Processing And Detection Limits
    Hazel, G.; Bucholtz, F.; Aggarwal, I. D. (Optical Society of America, 1997-05-01)
    A theoretical analysis of long-term drift noise in Fourier transform spectroscopy is presented. Theoretical predictions are confirmed by experiment. Fractional Brownian motion is employed as a stochastic process model for drift noise. A formulation of minimum detectable signal is given that properly accounts for drift noise. The spectral exponent of the low-frequency drift noise is calculated from experimental data. A frequency-dependent optimal spectrum averaging time is found to exist beyond which the minimum detectable signal increases indefinitely. It is also shown that the minimum detectable signal in an absorbance or transmission measurement degrades indefinitely with the time elapsed since background spectrum acquisition. (C) 1997 Optical Society of America.
  • Thumbnail Image
    Separation of Intrinsic and extrinsic Optical-Absorption in a Fluoride Glass
    Jewell, J. M.; Williams, Glen M.; Jaganathan, J.; Aggarwal, I. D.; Greason, P. (AIP Publishing, 1991-07-01)
    The contribution of impurity ions to the total optical absorption of a heavy metal fluoride glass has been determined at 532 and 1064 nm. Four ZrF4-BaF2-LaF3-AlF3-NaF glasses were prepared from various purity raw materials. The absorption coefficients of these glasses range from 0.92 to 45.4 x 10(-4) cm-1 at 1064 nm and from 7.43 to 11.1 X 10(-4) cm-1 at 532 nm as determined by laser calorimetry. The concentrations of Fe, Ni, Cu, and Co ions in each glass were determined by graphite furnace atomic absorption spectroscopy. These two measurements enable the absorption, due to transition metal ions to be differentiated from the intrinsic absorption of the glass. At 1064 nm, the absorption coefficient of these glasses is controlled entirely by the transition metal ion content. However, at 532 nm, the absorption by the transition metal ions accounts for 4-42% of the total absorption depending on impurity concentration. The intrinsic absorption of this fluoride glass calculated from these data at 532 nm is (7.69 +/- 0.99) X 10(-4) cm-1.