2017a Star


Extreme Siemen’s Star with annular breaks to improve readability.

Smallest feature is 300nm line pairs equal to 3,333 cycles per mm.

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Extreme resolution Siemen’s Star.  40 Spoke and Space pairs, from 6.37 cycles per millimeter at the outside circumference to 3,333 cycles per millimeter at the innermost terminus. This corresponds to 150 nanometer spoke or space width at the innermost terminus.

We improved the human readability of the Extreme Star by breaking the spokes with circular spaces at factor of 2 intervals, as the spoke pair period decreases. In order to make the Star even easier to use, at each break we numbered the minimum period with the size in microns . (Except the innermost 2 breaks. The spokes are so small the number features are below the critical dimension of the process). See the SEM images.

The Extreme Star was prepared at the direction of researchers at CalTech to support the Coherent Microscope Imaging Group though it has applications in any sort of microscopy. See Standardizing the resolution claims for coherent microscopy, Roarke Horstmeyer, et. al., Commentary in NATURE PHOTONICS, VOL 10, FEBRUARY 2016, www.nature.com/naturephotonics.

The Extreme Star is chrome plated on a 5.17 x 8.96 x 1 millimeter diamond-shaped quartz substrate. The diamond shaped substrate is mounted in a black, anodized-aluminum. microscope slide for easy human handling.

The Extreme Star can be purchased unmounted.

The chrome is firmly fixed, about 1,000 angstroms thick.

Product Summary
  • Model 2017a Star
  • Manufactured by: Ready Optics Company
  • 300 nanometer line pair resolution (150nm single spoke).
  • High Contrast Chrome on Quartz Glass
  • 2mm outside target diameter
  • 40 spoke-space pairs
  • 6.37 cycles per millimeter at the outside circumference
  • 3,333 cycles per millimeter at the innermost terminus
  • Circular breaks at 128, 64, 32, 16, 8, 4, 2, 1, 0.5, 0.3 microns per pair periods (spoke & space).
  • There is some rounding of the spokes at the inner terminus (0.3 µm period), please see the SEM photos.
  • Excellent for machine or human examination of resolution in all axes.


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