  Contemporary approaches to optical multiple micro-manipulation typically
involve careful pre-engineering of the laser beam shape. In various biomedical
and microfluidic scenarios, especially those necessitating unconventional
specimen chambers, there is a demand for controlling the collection of
micro-objects at fluid-fluid interfaces. This requirement arises in contexts
such as the transport of materials across liquid interfaces for applications
like living cell manipulation, drug delivery, soft functional material
creation, and various industrial processes. For many of these cases, a regular
array of trap sites as well as tightly confinement are not essential. For such
applications at interfaces, we expand on the concept of speckle tweezers (ST),
which incorporate randomly distributed light fields for quasi-2D optical
manipulation. The proposed technique is demonstrated experimentally by applying
ST to govern the movement of PS micro-particles at water-oil and water-air
interfaces. The efficacy of the method is validated through the temporal
characterization of micro-particle motions using digital video microscopy.
