Absolute terahertz power measurement of a time-domain spectroscopy system

Abstract

We report on, to the best of our knowledge, the first absolute terahertz (THz) power measurement of a photoconductive emitter developed for time-domain spectroscopy (TDS). The broadband THz radiation emitted by a photoconductor optimized for the excitation with 1550-nm femtosecond pulses was measured by an ultrathin pyroelectric thin-film (UPTF) detector. We show that this detector has a spectrally flat transmission between 100 GHz and 5 THz due to special conductive electrodes on both sides of the UPTF. Its flat responsivity allows the calibration with a standard detector that is traceable to the International System of Units (SI) at the THz detector calibration facility of PTB. Absolute THz power in the range from below 1 μW to above 0.1 mW was measured.

Norton Equivalent Circuit for Pulsed Photoconductive Antennas—Part II: Experimental Validation

“…Such results also provide a solid validation of the equivalent circuit model proposed in [10], which can be effectively used to design PCAs. photomixer to the detector with a QO system (the same as used to characterize it by the manufacturer [38], [39]) and scanning the frequency of the source over its bandwidth (i.e. 0.1 THz − 1 THz).…”

“…The error bars in the plot show the range as large as six standard deviation of the measurements at each frequency. Since the reference power was measured with a different detector [39], in order to have a fair comparison, the measurements have been corrected for the coupling efficiency η d of the detector [12]. The QO channel [38]- [40] has been analyzed as discussed in Section IV and the efficiency η d has been evaluated.…”

Towards Quality Control in Pharmaceutical Packaging: Screening Folded Boxes for Package Inserts

“…With an optical power of 20 mW and a DC bias of 120 V applied, the emitter generates an average terahertz power of approx. 75 μW [18].…”

Terahertz detectors from Be-doped low-temperature grown InGaAs/InAlAs: Interplay of annealing and terahertz performance

“…For all subsequent experiments a commercially available THz time-domain spectrometer operating with femtosecond laser-pulses centered around 1550 nm was used. 5 The fiber-coupled THz emitter was illuminated with 20 mW of optical power and biased with 120 V. 46 For an individual measurement 1000 pulse trace with a duration of 70 ps were recorded and averaged, leading to a total acquisition time of 60 s. The THz path consisted of two 2-inch 90 • off-axis parabolic mirrors with a focal length of 3-inch. All measurements were done in ambient air.…”