Spatial Narrowing of Two-Photon Imaging in a Silicon CCD Camera

Imaging based on nonlinear two-photon absorption can offer an attractive alternative for the traditional one-photon imaging scheme with many potential benefits of imaging resolution, speed, and ability to image through scattering media. Here we experimentally demonstrate a direct imaging scheme based on two-photon absorption in the conventional silicon CCD camera and observe a spatial narrowing effect in its imaging. This technique, compared with its one-photon counterpart, exhibits a better imaging resolution and signal-to-noise ratio, thanks to the nonlinear nature of the two-photon absorption process. This nonlinear imaging scheme opens up an avenue for rapid real-time and high-resolution imaging through scattering media like rain, fog, and biomedical samples.