Precision metrology with weak measurements using spin splitting of light

Since its first introduction over twenty years ago, weak measurements have gradually became an useful metrology tool in the laboratory. Due to its desirable amplification effect, a small physical variable can be detected with weak measurements. Spin splitting of light, which stems from the interaction between the spin and orbital angular momentum in optical reflection or refraction at the interface of mediums, is always a weak effect. However, the spin splitting of light can be detected easily with weak measurements. Remarkably, the spin splitting of light is sensitive to the physical parameter variations of system. Using the spin splitting as a probe, the physical parameter can be accurately estimated with weak measurements. Here, we review some of our works on precision metrology with weak measurements using the spin splitting of light as a probe, such as estimation of the magneto-optical constant of a magnetic film, determination of the focused beam waist, and measurement of the polarization state of light.