Spatial mode generation and detection by means of the sum-frequency upconversion process

The efficient creation and detection of spatial modes of light has become topical of late, driven by the need to increase photon bit-rates in classical and quantum communications. Here we put forward a new spatial mode detection technique based on the nonlinear optical process of sumfrequency generation, also showing that the method can be used to transfer an image from the infrared band to the visible, which implies the efficient conversion of many spatial modes.