Fiber Coupled Transceiver with 6.5 THz Bandwidth for Terahertz Time-Domain Spectroscopy in Reflection Geometry.

Robert B Kohlhaas,Björn Globisch,David De Felipe,Simon Nellen,Marcel Amberg,Martin Schell,Lars Liebermeister,Steffen Breuer

doi:10.3390/s20092616

Abstract

We present a fiber coupled transceiver head for terahertz (THz) time-domain reflection measurements. The monolithically integrated transceiver chip is based on iron (Fe) doped In0.53Ga0.47As (InGaAs:Fe) grown by molecular beam epitaxy. Due to its ultrashort electron lifetime and high mobility, InGaAs:Fe is very well suited as both THz emitter and receiver. A record THz bandwidth of 6.5 THz and a peak dynamic range of up to 75 dB are achieved. In addition, we present THz imaging in reflection geometry with a spatial resolution as good as 130 µm. Hence, this THz transceiver is a promising device for industrial THz sensing applications.

Highlights

The terahertz (THz) spectral range (0.1–10 THz) combines a diverse range of fundamental research questions and technically useful properties
The transceivers are characterized as sensor heads in THz time-domain spectroscopy (TDS) measurements in reflection geometry
We presented a monolithically integrated THz transceiver combining emitter and receiver on a single photoconductive chip based on Fe doped InGaAs

Summary

Introduction

The terahertz (THz) spectral range (0.1–10 THz) combines a diverse range of fundamental research questions and technically useful properties. Many materials of industrial and technical importance, such as ceramics, paper, (functional) coatings, automotive paint, or plastics are transparent in the THz range [1,2,3] This allows non-contact, non-destructive testing including defect identification/localization and the determination of layer thicknesses, even of multi-layered samples [4,5,6]. Due to the availability of mature and cost-efficient optical components and lasers at the telecommunication wavelength around 1550 nm, many commercially available THz systems exploit this technology. This enables all fiber-coupled THz TDS systems, which can be directly employed in industrial environments. The best-performing systems achieve a THz bandwidth of > 6 THz and up to

Methods

Results

Conclusion