Abstract-Single-shot electro-optic detection for intense terahertz pulses

Shixiang Xu

https://www.osapublishing.org/abstract.cfm?uri=ISUPTW-2018-TuB2

We report a single-shot terahertz common-path spectral interferometer based on electro -optic sampling, which can improve experimentally the measured signal-noise ratio (SNR) by 11.4 times compared with Mach-Zehnder interferometer.

© 2018 OSA

Abstract-Polarization-sensitive electro-optic detection of terahertz wave using three different types of crystal symmetry: Toward broadband polarization spectroscopy

Kenichi Oguchi¹, Hotsumi Iwasaki¹, Makoto Okano¹ and Shinichi Watanabe^1,a)
http://scitation.aip.org/content/aip/journal/apl/108/1/10.1063/1.4939510
1 Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
a) Author to whom correspondence should be addressed. Electronic mail:watanabe@phys.keio.ac.jp
Appl. Phys. Lett. 108, 011105 (2016); http://dx.doi.org/10.1063/1.4939510

We investigated polarization-sensitive electro-optic (EO) detection of terahertz (THz) waves by using two uniaxial crystals: a c-cut gallium selenide and a c-cut lithium niobate crystals. We formulated a general frequency-domain description of EO detection by in-plane isotropic EO crystals, which holds regardless of the frequency. Based on this description, the polarization of THz waves can be derived by analyzing EO sampling signals measured with two orthogonal configurations of the in-plane isotropic EO crystals as well as typical (111) zinc-blende EO crystals. In addition, we experimentally demonstrated that the frequency-dependent polarizationof THz waves can be reproducibly retrieved using three EO crystals with different crystal symmetries and with different phase matching conditions. Our description provides essential information for practical polarization sensing in the THz frequency range as well as in the mid-infrared range.

Abstract-Terahertz electro-optical detection: optical phase or energy measurements

 

S. P. Kovalev and G. Kh. Kitaeva  »View Author Affiliation
http://www.opticsinfobase.org/josab/abstract.cfm?URI=josab-30-10-2650

Models of different available single-photodetector electro-optic sampling schemes are considered from the unified theoretical position. It is taken into account that under electro-optic terahertz wave detection, not only do the polarization states of the femtosecond optical pulse components change but the modules of their amplitudes are also varied. As a result, information concerning the terahertz wave can be obtained not only using the conventional ellipsometry readout scheme (probe-phase sampling) but also by simple measuring of the induced power of the optical pulses (probe-energy sampling). Spectral sensitivities of both of these electro-optic sampling methods are calculated for the cases of nonlinear-optical crystals with zinc-blende symmetry (like ZnTe) and the crystals with one active component of the second-order optical susceptibility tensor (like PPLN). It is found that the ratio between spectral sensitivities of the pure probe-phase and pure probe-energy schemes is proportional to the ratio between the optical and terahertz wave frequencies in all types of the crystals. It is shown that the signal in the near-zero optical transmission point scheme, which is the best for terahertz imaging, has a mixed character. While the contribution of the probe-phase sensitivity appears to be due to spatially nonuniform residual birefringence of the nonlinear zinc-blende crystal, the probe-energy part of the sensitivity has a uniform distribution and can be increased by the angle misalignment of the optical polarization element.

© 2013 Optical Society of America