scholarly journals Electro-Optic Control of Lithium Niobate Bulk Whispering Gallery Resonators: Analysis of the Distribution of Externally Applied Electric Fields

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 298
Author(s):  
Yannick Minet ◽  
Hans Zappe ◽  
Ingo Breunig ◽  
Karsten Buse

Whispering gallery resonators made out of lithium niobate allow for optical parametric oscillation and frequency comb generation employing the outstanding second-order nonlinear-optical properties of this material. An important knob to tune and control these processes is, e.g., the linear electro-optic effect, the Pockels effect via externally applied electric fields. Due to the shape of the resonators a precise prediction of the electric field strength that affects the optical mode is non-trivial. Here, we study the average strength of the electric field in z-direction in the region of the optical mode for different configurations and geometries of lithium niobate whispering gallery resonators with the help of the finite element method. We find that in some configurations almost 100% is present in the cavity compared to the ideal case of a cylindrical resonator. Even in the case of a few-mode resonator with a very thin rim we find a strength of 90%. Our results give useful design considerations for future arrangements that may benefit from the strong electro-optic effect in bulk whispering gallery resonators made out of lithium niobate.

Nature ◽  
2019 ◽  
Vol 568 (7752) ◽  
pp. 373-377 ◽  
Author(s):  
Mian Zhang ◽  
Brandon Buscaino ◽  
Cheng Wang ◽  
Amirhassan Shams-Ansari ◽  
Christian Reimer ◽  
...  

2016 ◽  
Vol 108 (19) ◽  
pp. 191103 ◽  
Author(s):  
Yuto Suzuki ◽  
Kengo Osawa ◽  
Shunpei Yukita ◽  
Takayoshi Kobayashi ◽  
Eiji Tokunaga

2016 ◽  
Vol 41 (23) ◽  
pp. 5474 ◽  
Author(s):  
Markus Leidinger ◽  
Christoph S. Werner ◽  
Wataru Yoshiki ◽  
Karsten Buse ◽  
Ingo Breunig

Author(s):  
Robert E. Newnham

Optical beams can be controlled by manipulating the refractive indices and absorption coefficients with applied electric fields. In communication systems electro-optic effects are used in phase and amplitude modulation, in beam deflectors, and in tunable filters. Three such effects are illustrated in Fig. 28.1. Lead lanthanum zirconate titanate (PLZT) is a transparent electroceramic that can be prepared in several different ferroelectric forms with large electro-optic coefficients. When prepared in a normal ferroelectric form it can be used in two different ways. A light-tunable shutter is constructed by coating a multidomain ceramic of PLZT with a photoconducting layer and transparent electrodes. A bias voltage on the electrodes is transferred to the ceramic when the photoconductor is illuminated. The electric field alters the domain structure and the degree of light scattering, controlling the intensity of light. Fully poled ferroelectric ceramics exhibit the linear electro-optic effect Using planar electrodes the PLZT is poled perpendicular to the optical beam. Polarizer and analyzer are positioned in the ±45◦ positions, and light intensity is controlled by altering the birefringence with an electric field. The third experiment utilizes a pseudo-cubic PLZT composition with a large quadratic electro-optic effect. No poling is required in this case. With polarizer and analyzer again in the ±45◦ positions, the transmitted light intensity is proportional to E2 rather than E. Linear and quadratic electro-optic coefficients are defined in terms of the fieldinduced changes in the optical indicatrix: . . . Bij(E) − Bij(0) = Δ


2021 ◽  
Vol 29 (1) ◽  
Author(s):  
Mokhamad Tirono ◽  
Suhariningsih

Sterilization using high-intensity electric fields is detrimental to health if safety is inadequate, so it is necessary to study the possibility of sterilization using low-intensity electric fields. This study aims to determine the lowest electric field intensity and treatment time to deactivate the bacteria that make up the biofilms and explain the mechanism of inactivation. The study samples were biofilms from the bacteria Pseudomonas aeruginosa and Staphylococcus epidermidis grown on the catheter. The modeling formula was developed from the Pockels effect and the Weibull distribution with the treatment using a square pulse-shaped electric field with a pulse width of 50 μs and an intensity of 2.0-4.0 kV/ cm. The results showed that the threshold for irreversible electroporation of both samples occurred in the treatment using an electric field with an intensity of 3.5 kV/cm and 3.75 kV/ cm, respectively, where the size and type of Gram of bacteria influenced. Moreover, the time of the treatment had an effect when irreversible electroporation occurred. However, when there was reversible electroporation, the effect of treatment time on the reduction in the number of bacteria was not significant. Also, changes in conductivity affected the reduction in the number of bacteria when reversible electroporation occurred.


2020 ◽  
Vol 4 (4) ◽  
pp. 378-388
Author(s):  
Игорь Андреевич Гончаренко ◽  
Виталий Николаевич Рябцев ◽  
Александр Васильевич Ильюшонок ◽  
Олег Дмитриевич Навроцкий

Purpose. Development of the structure and operation principles of high frequency electric fields intensity optical sensor. Methods. Method of lines was used for calculation of propagation constants and mode electric fields distribution of strip waveguides with vertical and horizontal slots filled with electro-optical polymer SEO125. Findings. The structure and operation principles of high frequency electric fields intensity sensor on the base of slot waveguides with vertical and horizontal slots filled with electro-optical polymer are proposed. Sensor makes it possible measuring the variable electric fields with frequencies up to 10 MHz. The sensor sensitivity order is of 30 V/m. Application field of research. Determination of fire-dangerous and injurious factors of electric field during emergencies elimination.


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