State-of-the-art in cw photomixing systems

Frequency-domain terahertz techniques offer spectral selectivity, high resolution and excellent signal-to-noise ratios. Two-color distributed feedback (DFB) diode lasers now form the basis of compact and portable systems. Photomixers - photoconductors or fast p-i-n photodiodes - convert the optical beat signal of the two lasers into tunable, narrow-band terahertz radiation. Optimized laser tuning and data processing algorithms reduce the acquisition time for a complete spectrum from several hours to below 2 minutes. This talk compares THz systems based on GaAs photomixer technology and recent developments using InGaAs/InP emitters and detectors. Selected application examples are presented.