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Full-Text Articles in Physics
Logistic Curves, Extraction Costs And Peak Oil, Robert J. Brecha
Logistic Curves, Extraction Costs And Peak Oil, Robert J. Brecha
Physics Faculty Publications
Debates about the possibility of a near-term maximum in world oil production have become increasingly prominent over the past decade, with the focus often being on the quantification of geologically available and technologically recoverable amounts of oil in the ground. Economically, the important parameter is not a physical limit to resources in the ground, but whether market price signals and costs of extraction will indicate the efficiency of extracting conventional or nonconventional resources as opposed to making substitutions over time for other fuels and technologies. We present a hybrid approach to the peak-oil question with two models in which the …
Mid-Infrared Upconversion Spectroscopy Based On A Yb:Fiber Femtosecond Laser, Todd Johnson, Scott A. Diddams
Mid-Infrared Upconversion Spectroscopy Based On A Yb:Fiber Femtosecond Laser, Todd Johnson, Scott A. Diddams
Physics Faculty Publications
We present a system for molecular spectroscopy using a broadband mid-infrared laser with near-infrared detection. Difference frequency generation of a Yb:fiber femtosecond laser produced a mid-infrared (MIR) source tunable from 2100–3700 cm-1 (2.7–4.7 μm) with average power up to 40 mW. The MIR spectrum was upconverted to near-infrared wavelengths for broadband detection using a two-dimensional dispersion imaging technique. Absorption measurements were performed over bandwidths of 240 cm-1 (7.2 THz) with 0.048 cm-1 (1.4 GHz) resolution, and absolute frequency scale uncertainty was better than 0.005 cm-1 (150 MHz). The minimum detectable absorption coefficient per spectral element was …
Practicality Of Compensating The Loss In The Plasmonic Waveguides Using Semiconductor Gain Medium, Jacob B. Khurgin, Greg Sun
Practicality Of Compensating The Loss In The Plasmonic Waveguides Using Semiconductor Gain Medium, Jacob B. Khurgin, Greg Sun
Physics Faculty Publications
We consider the issue of compensating the loss in plasmonic waveguides with semiconductor gain material and show that, independent of specific geometry, full loss compensation in plasmonic waveguides with significantly sub-wavelength light confinement (less than λ/4n) requires current density well in excess of 100 kA/cm2. This high current density is attributed to the unavoidable shortening of recombination time caused by the Purcell effect inherent to sub-wavelength confinement. Consequently, an injection-pumped plasmonic laser that is truly sub-wavelength in all three dimensions (“spaser”) would have threshold current densities that are hard to obtain in any conceivable semiconductor device.