Ultrafast pump-probe signal detection using a data acquisition card

This work demonstrates the homebuilt, cost effective, pump probe signal detection using an advanced version of National Instrument data acquisition (NI-DAQ) card, which is used for multiple purposes in the same experiment. This advanced DAQ card is used as a controller for the linear stage, as an oscilloscope, and also for simultaneous acquisition of the signal from two photodiodes in synchronization with linear stage. The fast sampling rate of the DAQ card is used to quantify the peak power of the femtosecond laser pulse. This enables easier, faster, pulse to pulse data acquisition. A balanced detection technique is employed here, where the output from the two photodiodes are simultaneously sampled by the single DAQ card and is used to minimize pulse to pulse and slowly varying long-term fluctuations which are inherent to the laser source. We also review the significant developments in the DAQ card technology which helps to bypass the need for sophisticated instruments like lock-in amplifier or boxcar integrator, digital delay generator. This method is quite general and can be used in any experiment, where one needs to quantify the intensity variations in an experiment.