Abstract-CW-THz vector spectroscopy and imaging system based on 1.55-µm fiber-optics

Jae-Young Kim, Ho-Jin Song, Makoto Yaita, Akihiko Hirata, and Katsuhiro Ajito  »View Author Affiliations

http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-22-2-1735

Optics Express, Vol. 22, Issue 2, pp. 1735-1741 (2014)
http://dx.doi.org/10.1364/OE.22.001735

We present a continuous-wave terahertz (THz) vector spectroscopy and imaging system based on a 1.5-µm fiber optic uni-traveling-carrier photodiode and InGaAs photo-conductive receiver. Using electro-optic (EO) phase modulators for THz phase control with shortened optical paths, the system achieves fast vector measurement with effective phase stabilization. Dynamic ranges of 100 dB·Hz and 75 dB·Hz at 300 GHz and 1 THz, and phase stability of 1.5° per minute are obtained. With the simultaneous measurement of absorbance and relative permittivity, we demonstrate non-destructive analyses of pharmaceutical cocrystals inside tablets within a few minutes.

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