A transmission optical rotation detection scheme based on a weak measurement was proposed for the chirality detection of enantiomers. In this transmission weak measurement system in the frequency domain, the optical activity of the chiral liquid sample was estimated with the central wavelength shift, by modifying the preselected polarization state with the optical rotation (OR). The central wavelength shift of output spectra is sensitive to the OR angle but immune to the interference of the refractive index change caused by measuring circumstances. Two isomers of chiral amino acid acquired opposite responses with this system, and a resolution of 2.17 × 10−9 mol/ml for Proline detection could be obtained. Such a resolution is about 2 orders of magnitude higher than that of common methods, which shows a high sensitivity. This proposed weak measurement scenario suggested an approach to polarimetry and provided a way to accurately assess molecular chirality.

We describe a method that uses classic optical coherence tomography to measure the transverse fluid-flow velocity quantitatively without knowing the Doppler angle. An intensity based cross-correlation calculation is taken point-to-pointly between two close cross sections of the scattering fluid to estimate the time delay for scattering particles passing through the two sections which are scanned alternately. The transverse velocity distribution of the scattering fluid-flow in the whole section is achieved finally. The experimental results agree well with the preset ones. This method is insensitive to the Doppler angle and provides a variable velocity detection range in different application conditions.

A reflection-type phase-sensitive weak measurement for biosensing and chemical label-free sensing is presented. The phase difference between p and s polarizations in total internal reflection caused by biomolecular recognition is measured by weak value amplification. The system with p and s polarizations in a common path is stable and robust. The sensing process occurring on the silicon dioxide surface is achieved with a resolution of 3.6×10^-6 refractive index units. The applicability is demonstrated by real-time monitoring biomolecular interaction of IgG and protein A.