Overview
ISO 13696:2022 - "Optics and photonics - Test method for total scattering by optical components" specifies standardized procedures to measure total scattering from coated and uncoated optical surfaces. The standard covers measurement of the contributions from forward scattering and backward scattering, using an integrating element (Ulbricht/integrating sphere) as the primary collection method. Applicable components have surfaces with a radius of curvature greater than 10 m. Measurement wavelengths span from the ultraviolet above 250 nm through the infrared below 15 µm; special methods for the deep ultraviolet (190–250 nm) are included. Scattering is generally considered negligible above 15 µm.
Key topics and technical requirements
- Measurement principle: Collection of scattered radiation with an Ulbricht (integrating) sphere; Annex A describes a Coblentz hemisphere alternative.
- Measurement range: UV (>250 nm) to IR (<15 µm); deep-UV procedures (190–250 nm) specified.
- Specimen requirements: Applies to optical surfaces with radius of curvature >10 m; both coated and uncoated surfaces.
- Forward / backward scattering definitions: Clear half-space definitions and notes clarifying that measured forward or backward scattering is the reported total for that halfspace (the sum may not include bulk/volume scattering).
- Instrumentation and arrangement:
- Radiation source and beam preparation system
- Integrating sphere (Ulbricht) with defined acceptance angles (polar acceptance up to 85°; specular cone ~2° around the main beam is excluded)
- Detection system (photodetectors, optional lock‑in amplifier or fast data acquisition)
- Specimen holder and high-sensitivity arrangements
- Calibration & evaluation: Procedures include power calibration at the sample, unloaded-sphere baseline, formulas for total scattering, and an error budget. Annex E presents an alternative calibration using a calcium fluoride diffuser disk.
- Reference materials: Use of diffuse reflectance standards (e.g., barium sulfate, PTFE) and guidance on reflectance behavior.
Practical applications
ISO 13696:2022 is used to:
- Quantify scattering losses for laser optics, imaging lenses, mirrors and coatings.
- Support quality control and acceptance testing in optical component manufacturing.
- Provide traceable measurement procedures for metrology laboratories and optical test facilities.
- Inform system-level optical loss budgeting, stray-light analysis, and reliability assessments in photonics systems.
Who should use this standard
- Optical manufacturers and coating suppliers
- Laser system designers and integrators
- Optical test labs and calibration houses
- R&D teams in photonics, imaging, and metrology
Related standards
- ISO 11145 (optical vocabulary & symbols)
- ISO 14644-1 (cleanroom classification)
- ISO 11146 series (beam characterization) and other optics/metrology standards referenced in ISO 13696:2022
Keywords: ISO 13696:2022, total scattering, optical components, integrating sphere, forward scattering, backward scattering, Ulbricht sphere, Coblentz hemisphere, diffuse reflectance standard, deep ultraviolet scattering.
