Project Description

ASPE Topical Meeting – Precision Engineering & Optics: 24th – 25th April 2017

Further Information

ASPE Topical Meeting  24-25 April 2017
Westward Look Wyndham Grand Resort & Spa Tucson, Arizona, USA

This Topical Meeting will look at how well optics can be made and how to describe precision, particularly as a function of spatial scale of the optic or optical system. Because there is a partially accepted formalism for describing precision in optics by means of a power spectral density, or structure function, where precision is expressed as a function of the fractional size of the optic, can this same formalism be applied to other areas of precision engineering? Using precision in optics as a baseline, how do other fields of precision engineering stack up with methods of manufacture and metrology of optics?

We are soliciting papers that describe precision in all fields of engineering but in terms of angle measure so that independent of size, precision can be compared on a level playing field. For example, the LIGO test masses used to first detect a gravity wave were polished to 0.8 nm peak-to-valley over a diameter of 160 mm, or in angular terms, a variation of 5 nanoradians. Compared to this, for example, how precisely are features positioned on the latest silicon wafers during fabrication. At the other end of the spatial scale, how well aligned are the LIGO test masses at their separation of 4 km?

The idea for this meeting’s theme is an outgrowth of the Stedman diagram of the early 1990’s for characterizing metrology instruments in terms of their linear measurement range versus their slope measuring sensitivity. Can the same sort of comprehensive idea describe the limits of precision in terms of a metric based on the scale of features of the object in question? Further, how much of what is known about the precision of the object is inherent in the object and how much is a limitation of the metrology as a function of scale?

To seed the discussion, papers are solicited but not limited to topics such as:

  • Examples of precision on all size scales with results converted to angular terms
  • Specifications and methods of control of angles in optics and precision mechanics
  • Examples of describing precision based on the scale of features of the object such as a PSD or structure function
  • Fabrication technologies and their ability to control precision at different spatial frequencies
  • Methods for separating the errors in metrology from errors in the measurand, and the ideas of self-calibration or “absolute” testing
  • Methods for characterizing the transfer function of a metrology device
  • The relationship between specifications, actual optical surfaces and optical performance
  • Any fundamental limits to achieving precision

Although optics are the main emphasis of this Topical meeting, it is intended to be multi-disciplinary with examples of the limits of precision and means for describing and measuring them coming from all the disciplines in precision engineering. Ideas of how to measure and describe precision in one discipline may have applicability in another yet be rather unknown or in-applicable in another. The goal of this meeting is to bring ideas from many fields together in a small group setting so the ideas can be discussed in depth concerning limits to precision based on design, materials, assembly, fabrication techniques and metrology.