ISO/TR 14999-2:2019

Overview

ISO/TR 14999-2:2019 - "Optics and photonics - Interferometric measurement of optical elements and optical systems - Part 2: Measurement and evaluation techniques" provides guidance on interferometric measurement of optical surfaces and systems. The Technical Report explains measurement objects, hardware aspects of interferometers, evaluation methods (visual, manual, temporal and spatial phase techniques), and gives recommendations for test reports and calibration certificates. It complements the ISO 14999 series and optical drawing standards such as ISO 10110.

Key topics

• Measurement objects
  • Surface form, roughness, reflection degree, discontinuities and gradient/continuity of surfaces
  • Transmission components (windows, prisms) and single‑pass vs double‑pass testing
  • Full optical systems, pupil examination and chromatic aberrations
• Hardware and test environment
  • Interferometer construction principles, intrinsic instrument errors and common‑path designs
  • Error compensation strategies (optical and mathematical)
  • Test‑environment influences: vibrations, gravity, support and temperature homogeneity
• Evaluation methods
  • Visual inspection and manual evaluation of interferograms (examples: Fizeau and Twyman‑Green setups)
  • Phase measurement techniques with temporal carriers (heterodyne, phase‑lock, phase‑shifting)
  • Spatial carrier techniques and Fourier‑based fringe analysis
  • Phase unwrapping, wavefront registration, coordinate systems
  • Polynomial and orthogonal representations (Zernike, Legendre, annular forms) for wavefront data
• Reporting and data
  • Recommended content and format for test reports and calibration certificates
  • Guidance on electronic transmission, specifications after adjustment/repair, and data formats

Applications

ISO/TR 14999-2 is practical for organizations and professionals involved in optical metrology:

• Optical manufacturers verifying lens, mirror and prism form and wavefront quality
• Calibration and testing laboratories seeking guidance on calibration certificates and traceable reporting
• R&D and academic labs developing interferometric setups and analysis algorithms
• Quality and production engineers implementing standardized interferometric acceptance tests

Practical benefits include improved repeatability of interferometric measurements, clearer interpretation of interferograms, guidance on compensating instrument errors, and standardized reporting for procurement and compliance.

Related standards

• ISO 14999 series (other parts addressing complementary topics)
• ISO 10110 (preparation of drawings for optical elements and systems)

Keywords: interferometric measurement, interferometry, optical elements, optical systems, wavefront measurement, phase‑shifting interferometry, Fizeau, Twyman‑Green, Zernike polynomials, calibration certificate, test report.