# Up to 70 THz bandwidth from implanted Ge photoconductive antenna excited by a fibre laser

## TL;DR

This paper demonstrates a Ge-based photoconductive antenna capable of emitting ultra-broadband THz pulses up to 70 THz, significantly surpassing previous limits and enabling new applications in spectroscopy and photonics.

## Contribution

The authors developed a gold-implanted germanium emitter that achieves up to 70 THz bandwidth, compatible with fiber lasers and CMOS technology, representing a major advancement over traditional THz emitters.

## Key findings

- Achieved up to 70 THz bandwidth in THz emission.
- Compatible with fiber lasers at 1.1 and 1.55 μm wavelengths.
- Potential for compact, multi-THz photonic devices.

## Abstract

Phase-stable electromagnetic pulses in the THz frequency range offer several unique capabilities in time-resolved spectroscopy. However, the diversity of their application is limited by the covered spectral bandwidth. In particular, the upper frequency limit of photoconductive emitters - the most widespread technique in THz spectroscopy - reaches only up to 7 THz in regular transmission mode due to the absorption by infrared-active optical phonons. Here, we present ultra-broadband (extending up to 70 THz) THz emission from Au implanted Ge emitter which is compatible with a fibre laser operating at 1.1 and 1.55 {\mu}m wavelengths at a repetition rates of 10 and 20 MHz, respectively. This opens a perspective for the development of compact THz photonic devices operating up to multi-THz frequencies and compatible with Si CMOS technology.

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Source: https://tomesphere.com/paper/1906.08028