Abstract
We use mode-locked Ti:Sapphire Laser, wavelength 800nm, after being chirped pulse amplification and splitted, the power of per pulse is 12.8GW, pulse width 130fs, to pump insulated GaAs witch biased by DC voltage, and generate THz pulse with pulse width 5ps.We can get the time-domain spectroscopy of THz by electro-optic sampling.We let the THz signal pass through Ba2(Ti1-xSnx)9O20 x=0，0.024 sintered 4hrs and calculate the dielectric constant by effective-medium theory, and we compare the result with the dielectric constant at microwave range (4GHz). After that, we get several conclusions：1.The dielectric constants of the powdered samples are similar to sintered samples (about 39.5 and 38). 2.At the rage 0.1THz~0.6THz (besides 0.2TH), we also get the result that the Q values of x=0.024 are higher. 3.The power absorption coefficients of x=0 and 0.024 are different obviously, this may be caused by sintered or not.Application of THz Time-domain Spectroscopic Technique in Powdered Samples