Spectral Fresnel filter for pulsed broadband terahertz radiation

Xinrui Liu,Xi-Cheng Zhang,Nikolay V Petrov,Anton N Tcypkin,Yaroslav V Grachev,Mingzhao Song,Maksim S Kulya,Sergey A Kozlov

doi:10.1063/5.0024456

Xinrui Liu, Xi-Cheng Zhang + Show 6 more

Open Access

https://doi.org/10.1063/5.0024456

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Abstract

We proposed a simple and cost-effective method to manipulate the temporal and spectral properties of pulsed terahertz waves. A deep modulation of a pulse spectrum was both numerically and experimentally verified using Fresnel apertures with a radius ranging from several to several tens of the central wavelength of the broadband terahertz radiation. N-fold frequency minima were formed in the spectrum at a specific axial position behind the filter. Non-paraxial properties of this filter were also analyzed. A significant value (35%) of the ratio of the longitudinal to the transverse field component at the filter frequency was obtained. The measured results agree well with the simulation and theoretical predictions. The property of such a diffractive Fresnel notch filter can benefit the generation of longitudinal terahertz fields and relevant applications.

Highlights

Control over parameters of pulsed broadband radiation with an ultra-short duration is an important task for many applications
Fresnel zone plate (FZP) lenses and lens antennas have been frequently used as radiation, modulation, and imaging devices in THz electronic systems
The diffraction phenomenon on a circular aperture has been well discussed in the paraxial region,10 and the propagation properties of the highly non-paraxial region (R < λ) has been introduced for non-paraxial beams

Summary

Introduction

Control over parameters of pulsed broadband radiation with an ultra-short duration is an important task for many applications. A significant value (35%) of the ratio of the longitudinal to the transverse field component at the filter frequency was obtained.

Results

Conclusion