Variable-focus microlenses as a potential technology for endoscopy

Using a new device which contains an array of microlenses whose focal lengths can be electrically varied, we have been able to control the input from one microlens to a single mode fibre using an applied voltage. For such a microlens array many closely-spaced focal spots can be generated in parallel, and electrically switched to address, potentially, an array of receiver fibres. We show how the particular switching characteristics of the device, whereby the lenses switch from diverging to converging, serves in turn to disperse light and to focus it into the fibre.