Femtosecond Laser Fabrication of Metamaterials for High Frequency Microwave Devices

Abstract

The laser etching technique is used for configuration of micro-structures. Films of few-hundreds nm of gold deposited on glass or silicon are precisely processed by tightly focusing a femtosecond laser with 150fs pulse duration, 775nm wavelength, and energy of tens of nJ. The laser fluence is hold just above the ablation threshold. Thus, the evaporated film leaves behind structures with thin lateral size of about 1µm. Using this technique, the fabrication of micro-structures is demonstrated. The periodic structures are designed to behave as a left handed metamaterial in the GHz range. The fabricated metamaterials have applications for antenna, filters, couplers in the high frequency bands of microwave spectral range.