Fluorescence up-conversion is similar to the photoluminescence technique but instead of using a photodetector and electronics to measure the delay time of the emitted photon, it uses an optical gate. By combining the emitted photon with an 800 nm pulse in a BBO crystal and measuring the up-converted light it is possible to measure the photoluminescence with a temporal resolution of 50 fs. The instrument is equipped also with a photomultiplier that allows Time-Correlated Single-Photon Counting (TCSPC) measurements.