Pulsed THz sensing of dielectric thin films using cascaded filter arrays

The on-chip detection of nanolitre volumes of dielectric material is demonstrated using terahertz (THz) pulses. Simultaneous analysis at different frequencies on separate, lithographically defined locations is shown to be possible using THz band-stop filter elements connected by a microstrip line. Integrated thin film low-temperature-grown GaAs photoconductive switches are used for THz pulse generation within the microstrip interconnect. This technique is expected to be useful in sensing organic films such as DNA, and other biomolecular materials, in an on-chip environment.