Development of thick metal mesh THz-filters by LIGA-technology for high-power applications at Novosibirsk terahertz FEL

In this paper we report about initiating technological development of thick metal mesh structures intended for frequency filtration of high-power terahertz radiation of Novosibirsk free electron laser. The technology is based on the promising LIGA-technique which employs the effect of high penetrability of X-rays into roentgenosensitive resistive layers and destined for manufacturing microstructures with extremely high aspect ratios. Due to high metallization thickness comparable with radiation wavelength LIGA-structures are expected to be much more mechanically firm and thermostable than conventional photolithographic filters, as well as to provide much higher low-frequency attenuation due to a waveguide cutoff effect. The main stages of the LIGA-technique being mastered in the Siberian Synchrotron Radiation Center are described in the paper.