A Rapid Fabrication of Novel Dual Band Terahertz Metamaterial by Femtosecond Laser Ablation

Abstract

In this paper, we present a novel dual-band, polarization insensitive terahertz metamaterial design, numerical simulation, and its fabrication using femtosecond laser ablation process. The proposed design uses periodic patterned copper metallic structure on the polyimide thin film and provides dual resonant characteristics at 0.25 THz and 0.42 THz, respectively. The structure was simulated numerically using CST Microwave studio software and obtained the bandstop characteristics of – 22 dB at both the resonances. The obtained 10-dB bandwidth in numerical simulation at the first and second resonance was 11.7 GHz and 14 GHz, respectively. The normalized transmission, electric field, and the surface current distributions were analyzed for understanding the mechanism of dual-band resonance. In addition, the effect of geometrical parameters on the resonances has been discussed. The simulated structure was fabricated using 800 nm wavelength 100 fs Ti: Sapphire laser and the laser parameters were optimized for the ablation process. The characterization of the fabricated structure has been done using terahertz time-domain spectroscopy (THz-TDS) technique. The measurement results show that the fabricated structure has obtained polarization insensitive and angular stable transmission response.