Fig. 2: TLPDV experimental schematic.

a Simplified four-wave mixing based time-lens diagram. Two pump photons are annihilated to create a signal and an idler photon which is stimulated by the signal photon. Interaction between a chirped pump pulse and a CW signal results in a chirped idler which has the phase and amplitude information from signal and a linear chirp from the pump. A local oscillator is combined with the PDV laser prior to the time lens and therefore creates its own chirped idler. Linear chirp implies quadratic temporal phase which is analogous to quadratic spatial phase for a free-space lens. Similar to the spatial imaging equation, a temporal imaging equation can be written which depends on the pump, signal and the idler dispersions. b Experimental diagram for the time lens is shown with 3 arms: the pump, the signal and the idler. The return signal from the PDV enters the time lens through the signal arm. Pump arm starts with a broad band mode locked laser which is filtered, chirped and amplified. Pump and the signal are combined and sent to a highly nonlinear fiber (HNLF). The inset shows the measured spectra at the output of the HNLF. Idler is filtered out, chirped and amplified. A programmable filter is used at the end to filter out any pump leakage. The inset shows the idler after detection, digitization, gain equalization and normalization.