Properties of Terahertz Wave Emission from Nano-porous Gold Excited by Femtosecond Laser Pulses

We studied properties of terahertz wave emission from gold film with random nano-porous structures excited by femtosecond laser pulses. The emitted terahertz power grew almost twice faster for excitation at 800 nm than at 400 nm. We also measured the temperature dependence of the terahertz power, and found that the terahertz emission at 200 K was much stronger than that at room temperature.