Abstract-Highly precise and accurate terahertz polarization measurements based on electro-optic sampling with polarization modulation of probe pulses

Natsuki Nemoto, Takuya Higuchi, Natsuki Kanda, Kuniaki Konishi, and Makoto Kuwata-Gonokami  »View Author Affiliations

http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-22-15-17915

Optics Express, Vol. 22, Issue 15, pp. 17915-17929 (2014)
http://dx.doi.org/10.1364/OE.22.017915

We have developed an electro-optic (EO) sampling method with polarization modulation of probe pulses; this method allows us to measure the direction of a terahertz (THz) electric-field vector with a precision of 0.1 mrad in a data acquisition time of 660 ms using a 14.0-kHz repetition rate pulsed light source. Through combination with a THz time-domain spectroscopy technique, a time-dependent two-dimensional THz electric field was obtained. We used a photoelastic modulator for probe-polarization modulation and a (111)-oriented zincblende crystal as the EO crystal. Using the tilted pulse front excitation method with stable regeneratively amplified pulses, we prepared stable and intense THz pulses and performed pulse-by-pulse analog-to-digital conversion of the signals. These techniques significantly reduced statistical errors and enabled sub-mrad THz polarization measurements. We examined the performance of this method by measuring a wire-grid polarizer as a sample. The present method will open a new frontier of high-precision THz polarization sensitive measurements.

© 2014 Optical Society of America