Optical sensing is provided with a large sensing area in a thin package. For example, embodiments can operate in context of an under-display optical fingerprint sensor integrated into an electronic device, such as a smartphone. Responsive to reflected probe light passing through a display module, a reflective structure is configured to redirect the reflected probe light onto a refractive structure, and the refractive structure is configured to converge the reflected probe light into an input aperture of an optical sensor for detection. Some embodiments operate in context of an enhancement panel having micro-prism structures that tend to blur the reflected probe light. In such context, embodiments are configured for off-axis detection to prefer light passing through only certain micro-prism faces, thereby mitigating blurring.