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Electric field detection has been widely utilized in many fields such as scientific research and integrated circuits. To enhance the tuning sensitivity of E-field sensor, in this paper, we theoretically proposed a highly sensitive E-field sensor composed of etchless lithium niobate (LN) material and hybrid coupling-grating systems in the visible near-infrared regime. Such configuration supports high-quality factor quasi-BIC resonance, which generates strong localized field confinement. Due to the large electro-optic coefficient of LN material, one can shift the wavelength and reflection ratio of resonance by tuning the refractive index of LN material. An analytical theory is carried out to explain the relationship between the refractive index variations and the applied voltages, so we successfully obtained a tuning sensitivity of 40.8 nm/V and a minimum detectable electric field amplitude of 24.5 mV with wavelength resolution of 1 nm. Due to the low parasitic capacitance of LN material and high conductivity of gold film and ITO layer which are utilized as the electrodes, the 3dB bandwidth of the devices should exceed 154 GHz. And we believe that such a surface-normal E-field sensor has extensive potential for the extremely weak electric field detection., Comment: 10 pages, 5 figures

In this paper we present a new auto-microscope system controlled by microcomputer for image processing. The microstructure of objects can be observed and processed. A charge-coupled device (CCD) array is used as the photoelectric detector. This auto-microscope system can complete autofocusing, recognizing or screening out pattern in the field of view and automatic measuring for photomicrographing by the light intensity information sampling by CCD array. For this auto-microscope system we designed the scanning mechanism of microscope stage, adjustable holder of CCD in 5-Dimention, autofocusing mechanism and a auto-photomicrograph camera with large cassette. The autofocusing discrimination function constructed by means of self entropy is better suitable for low contrast image produced by microscope system. The geometrical features of the microscope image are selected for composing the discrimination function and this discrimination function is used for classifing the patterns in the microscope field of view by training samples. Automatically measuring light for photomicrograph is realized by the same CCD array and the controlling circuit, interface circuit and other circuits of this system are developed. Some experiments results: autofocusing, auto-screening the cell pattern in the microscope field of view are given.