Tunable dielectric liquid lens on flexible substrate.

We demonstrate the fabrication of a tunable-focus dielectric liquid lens (DLL) on a flexible substrate made of polydimethylsiloxane, which was wrapped onto a goggle surface to show its functionality. As a positive meniscus converging lens, the DLL has the focal length variable from 14.2 to 6.3 mm in 1.3 s when the driving voltage increases to 125 Vrms. The resolving power of the DLL is 17.95 line pairs per mm. The DLL on a flexible, curvilinear surface is promising for expanded field of view covered as well as in reconfigurable optical systems.

Three-dimensional illumination system using dielectric liquid lenses.

A 25-pixel illumination system composed of a 5 × 5 dielectric liquid-lens (DLL) zoom module array, 25 light-emission diodes (LEDs), and a secondary optical lens demonstrates 3D light field manipulation. LEDs function as 2D illumination pixels while the DLL module array performs longitudinal illuminance adjustability by zooming each illumination pixel. A test on the similarity of two illuminance patterns between experiments and simulations shows a normalized cross correlation (NCC) higher than 0.8, indicating the feasibility of the system design. Also, the illumination system is further applied to correct a distorted light pattern on a 45° tilt screen as well as to perform light compensation on distance-differential objects.

Cell rotation using optoelectronic tweezers.

A cell rotation method by using optoelectronic tweezers (OET) is reported. The binary image of a typical OET device, whose light and dark sides act as two sets of parallel plates with different ac voltages, was used to create a rotating electric field. Its feasibility for application to electrorotation of cells was demonstrated by rotating Ramos and yeast cells in their pitch axes. The electrorotation by using OET devices is dependent on the medium and cells' electrical properties, the cells' positions, and the OET device's geometrical dimension, as well as the frequency of the electric field.

Self-assembled high NA microlens arrays using global dielectricphoretic energy wells.

Microlens arrays were self-assembled from microballs using dielectrophoretic energy wells. Energy wells defined by patterned dielectric were used to produce microlens arrays with array patterns of desire. Microballs of 25microm in diameter were measured to have numerical aperture of 0.8 and focal length of 15.5microm. The optical resolution was found to be 0.4microm. Both the numerical aperture and the focal length were further adjusted to 0.66 and 19.0microm by a post-assembly heat treatment at 190 degrees C for 5 minutes.