1 Scope
This part of GB/T 7962 specifies the test method principle, test steps and data processing for the optical homogeneity of colourless optical glass by holographic interferometry.
This part is applicable to the measurement for optical homogeneity of colourless optical glass by holographic interferometry.
2 Normative references
The following documents contain provisions which, through reference in this part of GB/T 7962, constitute provisions of this part. For dated references, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest editions apply to this part.
GB/T 903 Colourless optical glass
3 Principle
Measure the change of optical path by interferometry, and calculate the corresponding refractive index differential Δn based on the number of interference fringes.
Based on the typical interference concept, derive the interference equations for the reflection interference fringes and the transmission interference fringes of the sample under test. Under certain boundary conditions, obtain the mathematical expressions of refractive index differential Δn and thickness differential Δh of the sample by two simultaneous equations. Record the two groups of fringes on the same hologram based on the double-exposure holography differential holographic interferometry principle, so as to obtain Δn and Δh from the reconstructing hologram (reconstructed wave surface).
Foreword i
1 Scope
2 Normative references
3 Principle
4 Apparatus
5 Sample
6 Measurement
Annex A (Informative) Judgment for optical homogeneity class by image recognition
Annex B (Informative) Judgment for optical homogeneity class by image recognition and table look-up
