Terahertz electro-optical detection: optical phase or energy measurementsстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 20 апреля 2016 г.
Аннотация: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.