Live Electrooptic Imaging of $W$-Band Waves

Abstract

A novel method for real-time visual observation of traveling -band waves is described. Wave images and movies are acquired by a live electrooptic imaging (LEI) camera equipped with an optical source that emits signals modulated at a local oscillator (LO) frequency in the -band range. Waves propagating in a slab waveguide made of a semiconductor plate as well as in the air are successfully visualized. Especially in this paper, -band wave images for the aerial propagation in a variety of forms are presented: spherical and plane waves together with some fundamental wave phenomena such as reflection, interference, and diffraction at metal-air interfaces. The principle of 100-GHz optical LO signal generation at the optical wavelength of 780 nm as well as performance parameters such as the spatial resolution, bandwidth, and dynamic range of the camera are discussed. Further, some preliminary applications of the scheme are presented.Index Terms-Electrooptic (EO) effects, imaging, millimeter-wave measurements, millimeter-wave propagation, millimeter-wave radio propagation.

Resolution of live electrooptic imaging with a very thin (10-µm) sensor plate

“…Besides various numerical visualization approaches, a technique named live electrooptic imaging (LEI) [1,2,3] shown in Fig. 1a is unique for approaching the above target experimentally, where high-frequency electric fields are visualized in real-time phase-evolving video formats.…”

“…Recently, the scheme of detached EO imaging [17] has been added to the list. The present status of the LEI technique is specified by its highest frequency of visualized waves, largest visional area, highest optical magnification ratio, and maximum pixel number, which are 100 GHz [2], 25-mm square [3], 8.5 [2], and 256 Â 256 ¼ 65;536 [18], respectively. One of the LEI issues needed to elucidate is its ultimate image resolution in the microscopic range.…”

Live Electrooptic Imaging Camera for Real-Time Visual Accesses to Electric Waves in GHz Range

“…The resolution is of course modified by the z-dependence of electrical field distributions as well as by the optical magnification factor described in 3-3. Details of these configurations are in our previous publications [6]～ [8] and, therefore, only brief explanations are given here. An optical local oscillator (LO) signal is generated at a frequency f LO with a 780 nm semiconductor laser and a Mach-Zehnder interferometer modulator.…”

Asynchronous live electrooptic imaging and its application to free-running broadband signal sources

“…The technique named live electrooptic imaging (LEI) [1,2,3] shown in Fig. 1a is unique for enabling this functionality experimentally, where electric fields in the microwave frequency range are displayed in real-time phase-evolving video formats.…”

“…Recently, the scheme of detached EO imaging (DEI) [17] was added to the list. The present status of the LEI technique [3] is specified by its highest frequency of visualized waves, visional area, highest optical magnification ratio, and maximum pixel number, which are 100 GHz [2], 25-mm square [3], 10 [2], and 256 Â 256 ¼ 65;536 [18], respectively.…”