Refractive-index measurements by moire deflectometry

Abstract

A novel method for measuring refractive index of gases and liquids is presented based on moire deflectometry. We demonstrate this technique by measuring the refractive index of diluted sucrose solutions and of air at atmospheric pressure.

Bulge Testing Transparent Thin Films with Moiré Deflectometry

“…A moiré deflectometry apparatus [23] for measuring the focal length of a lens structure is shown in Fig. 1(a).…”

“…1(c)] is the point corresponding to C with the same Z position on the moiré pattern formed without the lens. Notice that the deflection of beams is equivalent to the movement of G 1 relative to G 2 and the ratio of the corresponding shift of moiré fringes to this relative movement is [18,23] …”

“…Note that, compared to f=D/θ tan α obtained in [23], a term D+D 0 has been added, which accounts for situations where D+D 0 is significant fraction of f, which is certainly the case in bulge testing. Recalling equations (8) and (15), the determination of Young's modulus is sensitive to the measured R to the third power.…”

“…In the following, a better governing equation proposed by Williams [21] and later confirmed by Wan et al [22] is used. The general governing equation for moiré deflectometry to determine the focal length of a lens structure is updated by supplementing the previous derivation [23], which is only exact for an infinite focal length. These analyses are summarized in "Theoretical Background".…”

Improved regularized phase-tracking technique for the processing of squared-grating deflectograms

“…1,2 The applications of the technique range from reflectivesurface analysis 3 to the measurement of refractive index and temperature distribution. 4,5 In our particular case the application objective is to determine the power distribution in ophthalmic lenses. The experimental setup we used is shown in Fig.…”