Thursday, October 11, 2018

Abstract-Terahertz generation with ballistic photodiodes under pulsed operation


We investigate high field and ballistic carrier transport in a 1.55 μm photomixing
 device based on pin-diodes by time resolved terahertz (THz) spectroscopy. The device
 consists of 3 stacked In(Al)GaAs pin diodes (n-i-pn-i-p superlattice) attached to a
 broadband logarithmic-periodic antenna. Each pin diode is optimized for exhibiting
 ballistic transport and a reduced transit time roll-off. Ballistic transport signatures
 could be confirmed directly in these experiments. The data are compared with results
 from continuous-wave (CW) experiments and from simulations both supporting our
 theoretical expectations. It is demonstrated that n-i-pn-i-p superlattice photomixers
 are also efficient THz emitters under pulsed operation, showing a maximum THz field
 strength of ~0.5 V/cm (peak to peak) at 30 mW average optical power.

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