A method is provided for determining a thickness L of a chiral slab that refracts incident linearly polarized light into right (+) and left (−) circularly polarized beams. The method includes disposing the slab in an achiral medium, determining values of translation coefficients γ±, determining values for refraction angle differences (θ+−θ−), selecting pre- and post selection states |ψi and |ψj, projecting an emitted light beam through said achiral medium into the chiral slab a small established angle of incidence θ0, varying slab egress phase angles β±, determining said pointer mean value x, calculating weak value Aw, and calculating the thickness as L = 〈 x 〉 Re ⁢ ⁢ A w . The achiral medium has an established index of refraction n0. The translation coefficients γ± establish refraction translation differences (γ+−γ−). The pre-selection state |ψi establishes pre-selection alignment angle to satisfy Φ=π/4. The post-selection state |ψj establishes post-selection alignment angle to satisfy χ=Φ−ε and 0 0 or else a minimum for (γ+−γ−)