Open AccessHighly precise and accurate terahertz polarization measurements based on electro-optic sampling with polarization modulation of probe pulses
Author(s) -
Natsuki Nemoto,
Tohru Higuchi,
Natsuki Kanda,
Kuniaki Konishi,
Makoto KuwataGonokami
Publication year - 2014
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.22.017915
Subject(s) - terahertz radiation , optics , polarizer , materials science , polarization (electrochemistry) , terahertz spectroscopy and technology , electric field , optoelectronics , optical rectification , laser , physics , nonlinear optics , birefringence , chemistry , quantum mechanics
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.