Evaluation of BNA and boxcar averaging for enhanced 2D Time-Domain Terahertz Spectroscopy

Time-domain Terahertz (THz) spectroscopy is an ever-expanding field of experimental study, particularly in the quest to detect non-linear dynamics in materials. A limitation of traditional THz pump-probe setups is that they primarily probe linear responses, which restricts the exploration of complex material dynamics. To overcome this limitation, researchers have developed two-dimensional time-domain schemes that utilize two THz pump pulses, allowing for the measurement of responses that differ from the sum of the individual pulse effects. This has revealed new non-linear excitations of magnons in magnetic materials, for example, but the experiments are quite challenging in terms of optical alignment and data acquisition timescales. Here we explore the use of simpler optical setups combined with ultrafast multiplexed Boxcar averaging to speed up acquisition times and reduce noise. We will report on the system performance in studying non-linear excitations of antiferromagnetic magnons and describe new measurement modalities that can be added through the acquisition method.