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

• DOI: 10.1063/5.0221211
• Publication Date: 2024-08-29T11:29:26Z
• Authors: E. G. Tsiplakova; Y. V. Grachev; N. V. Petrov
• Keywords: Raster scan; Aperture (computer memory)

The measurement of the spatial distribution nearly monocyclic terahertz (THz) fields by a raster scanning diaphragm is widely used approach in THz pulse time-domain holography (PTDH) applied imaging, optical component design, and wavefront sensing tasks. However, it historically plagued compromise between balance signal-to-noise ratio (SNR) resolution. To address this challenge keep both parameters at high level, we proposed to replace aperture with module containing conjugated lens. This solution allowed us for first time experimentally investigate spatio-temporal dynamics Gauss–Bessel beam generated widespread low-energy system based on femtosecond laser energy around dozen nanojoules repetition rate tens megahertz. In particular, observe temporal spectrum field periphery SNR ≈0.5, which was not possible using conventional system. A careful numerical analysis reveals signal enhancement spectral domain approximately 2.5 times compared PTDH scan detection employing only diaphragm. Moreover, have shown that given ensures profiles remain unaffected quadratic phase aberration experienced single aperture.