Abstract-Common-path spectral interferometry for single-shot terahertz electro-optics detection

Shuiqing Zheng, Xinjian Pan, Yi Cai, Qinggang Lin, Ying Li, Shixiang Xu, Jingzhen Li, and Dianyuan Fan

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-42-21-4263

We propose a common-path spectral interferometer for single-shot terahertz (THz) electro-optics (EO) detection, where a probe pulse pair with orthogonal polarizations and a relative time delay are generated by simply using a birefringent plate. One of them, as the object, transmits through a THz EO crystal with THz phase modulation, while the other goes through the crystal without any phase imposed by target the THz field as the reference. The co-axial propagation of the pulse pair can effectively reduce the noises due to mechanical vibrations, air turbulences, and temperature fluctuations in the traditional non-common-path spectral interferometers. Our experiments show that, for a given target THz pulse field, the measured THz signals in a single-shot mode have a signal-to-noise ratio (SNR) of 41.2 with our THz common-path spectral interferometer, but 7.91 with a THz Mach–Zehnder spectral interferometer; thus, our design improves the SNR of the THz signal by about 5.2 times.

© 2017 Optical Society of America

Abstract-Self-referenced single-shot THz detection

Brandon K. Russell, Benjamin K. Ofori-Okai, Zhijiang Chen, Matthias C. Hoffmann, Ying Y. Tsui, and Siegfried H. Glenzer

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-14-16140&origin=search

We demonstrate a self-referencing method to reduce noise in a single-shot terahertz detection scheme. By splitting a single terahertz pulse and using a reflective echelon, both the signal and reference terahertz time-domain waveforms were measured using one laser pulse. Simultaneous acquisition of these waveforms significantly reduces noise originating from shot-to-shot fluctuations. We show that correlation function based referencing, which is not limited to polarization dependent measurements, can achieve a noise floor that is comparable to state-of-the-art polarization-gated balanced detection. Lastly, we extract the DC conductivity of a 30 nm free-standing gold film using a single THz pulse. The measured value of σ0 = 1.3 ± 0.4 × 107S m−1 is in good agreement with the value measured by four-point probe, indicating the viability of this method for measuring dynamical changes and small signals.

© 2017 Optical Society of America