By controlling the rotation rate of a trapped birefringent particle with an optically applied torque, the authors introduce a miniscule wave front deformation at a specific location within an arbitrary light field, with the particle acting as an optical microdiffuser. A trapped birefringent particle and a trapped silica microsphere are positioned to form Young's double slit experiment within a probe light field. The far-field interference from the diffracted optical fields from these particles enable the authors to infer the relative spatial coherence between these local sampling points. With multiple trapped particles, the authors may perform multipoint coherence analysis of a light field.
Bibliographical noteFunding Information:
This work is supported by the European Science Foundation grant NOMSAN which was supported by funds from the UK Engineering and Physical Sciences Research Council and the European Framework 6 Programme. One author (W.M.L.) acknowledges Einst Technology Pte Ltd. for the support and Klaus Metzger for his technical assistance.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)