| 摘要 |
The invention relates to control of THz radiation (25) in parallel plate waveguides (PPWG) by forming components in the waveguide (11) by use of optical radiation. Patterns of excited regions induced in the PPWG (11) by an optical excitation beam (28) changes the electromagnetic properties of the waveguide medium in the THz regime, thereby forming passive and active components for controlling THz radiation signals (25). The excitation can be generation of free charge carriers in a semiconductor material (14) in the PPWG, to create metallic regions that form mirrors, lenses or photonic crystal structures in the PPWG. The photo-induced pattern can be modulated in time in response to an incoming signal, to frequency-, phase- or amplitude-modulate the THz signal. The systems can be integrated on chip-scale components and can be applied in e.g. THz communication, digital computing, sensors, and lab-on-a-chip applications. The optical and THz radiation can be ultrashort pulses with picesecond or femtosecond pulse durations. |
