Spectrograph stabilization using a single-delay interferometer
AssigneeLawrence Livermore National Security, LLC
InventorDavid J. Erskine
Life of this patent
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Abstract
Methods, systems and devices are described that improve optical spectroscopic techniques and particularly those that involve externally dispersed interferometer (EDI) techniques that result in an output spectrum having improved stability characteristics. The output spectrum minimizes the unwanted shifts in wavelength when the spectrograph component of the EDI instrument is under stresses that would otherwise shift or distort the wavelength positions of the spectrum.
Claims24
A method for obtaining spectral characteristics of an optical signal, the method comprising:
- receiving information representing measured optical signals produced by an externally dispersed interferometer;
- determining a nonfringing component from the received information;
- obtaining an adjusted fringing component from the received information by at least:
- determining a fringing component from the received information, the fringing component having a range of frequencies;
- upshifting frequencies of the fringing component to reverse the interferometer heterodyning;
- removing frequency components in an upper section of the range of frequencies of the fringing component, and
- adjusting magnitudes of frequency components in a lower section of the range of frequencies of the fringing component based on one or more weights;
- combining the nonfringing component with the adjusted fringing component to produce a combined output spectrum;
- and
- performing an equalization operation to modify a shape of the combined output spectrum.
An externally dispersed interferometric system, comprising:
- an interferometer configured to receive light from an object, the interferometer having a single fixed-valued delay;
- a spectrograph positioned to receive optical signals output from the interferometer and to produce spectrally dispersed optical signals;
- a detector positioned to receive the spectrally dispersed optical signals from the spectrograph and to produce information representing signals detected thereon;
- and
- a processor and a memory including instructions that are stored thereon, wherein the instructions when executed by the processor configure the processor to:
- receive information representing measured optical signals produced by the detector,
- determine a nonfringing component from the received information,
- obtain an adjusted fringing component from the received information by at least:
- determining a fringing component from the received information, the fringing component having a range of frequencies;
- upshifting frequencies of the fringing component to reverse the interferometer heterodyning;
- removing spatial frequency components in an upper section of the range of frequencies of the fringing component, and
- adjusting magnitudes of frequency components in a lower section of the range of frequencies of the fringing component based on one or more weights;
- combine the nonfringing component with the adjusted fringing component to produce a combined output spectrum;
- and
- perform an equalization operation to modify a shape of the combined output spectrum.
Dependencies are inferred from the claim text.