Overcoming the trade-off between signal-to-noise ratio and resolution in holographic registration of pulsed terahertz Gauss–Bessel beams.

This article focuses on improving terahertz (THz) pulse time-domain holography (PTDH) by introducing a scanning module that combines a conjugated diaphragm and lens to enhance signal-to-noise ratio (SNR) without sacrificing spatial resolution. The modified scanning system enables collimation of the divergent THz radiation behind the diaphragm, resulting in approximately a 2.5-fold signal enhancement compared to conventional diaphragm-only raster scanning, even at long propagation distances. Using this approach, the authors experimentally measured the spatio-temporal evolution of broadband THz Gauss–Bessel beams generated by a low-energy femtosecond laser system, achieving observations previously unattainable with standard methods. Numerical simulations further confirmed that the diaphragm-lens system preserves temporal pulse profiles by avoiding quadratic phase aberrations and supports high-resolution imaging with improved sensitivity, offering potential benefits for THz holography and super-resolution THz imaging applications.