Experimental evaluation of achromatic phase shifters for mid-infrared starlight suppression

Appl Opt. 2009 Feb 10;48(5):868-80. doi: 10.1364/ao.48.000868.

Abstract

Phase shifters are a key component of nulling interferometry, one of the potential routes to enabling the measurement of faint exoplanet spectra. Here, three different achromatic phase shifters are evaluated experimentally in the mid-infrared, where such nulling interferometers may someday operate. The methods evaluated include the use of dispersive glasses, a through-focus field inversion, and field reversals on reflection from antisymmetric flat-mirror periscopes. All three approaches yielded deep, broadband, mid-infrared nulls, but the deepest broadband nulls were obtained with the periscope architecture. In the periscope system, average null depths of 4x10(-5) were obtained with a 25% bandwidth, and 2x10(-5) with a 20% bandwidth, at a central wavelength of 9.5 mum. The best short term nulls at 20% bandwidth were approximately 9x10(-6), in line with error budget predictions and the limits of the current generation of hardware.

Publication types

  • Evaluation Study

MeSH terms

  • Algorithms*
  • Artifacts*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Spectrophotometry, Infrared / methods*
  • Stars, Celestial*