Calibration for Frequencies of Stellar Spectral Lines
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Date
2010-07-14
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Abstract
When studying the expansion of the universe, a significant problem is measuring the red shifts of stellar absorption lines with sufficiently high accuracy; this requires extremely accurate reference frequencies for calibration. An important recent development is the use of laser frequency combs to provide the calibration frequencies. However, this approach is very time consuming and expensive. We are proposing a simple calibration approach using weak molecular absorption lines.
Our new approach is based on our recent development of a new diffuse reflecting surface whose reflectivity far exceeds anything previously available. Consider a basketball size cavity whose wall is made of this new diffuse reflector. Due to the high wall reflectivity, the effective absorption path length for light bouncing around inside this cavity is on the order of a kilometer. Consequently, even molecules with very weak absorption lines will show strong distinct absorption lines that can serve as calibration frequencies.
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redshift, infrared, weak stellar spectral lines