HIGH-FREQUENCY ELECTRO-OPTIC COEFFICIENTS OF LITHIUM NIOBATE

Author(s):  
E.H. Turner
2019 ◽  
Vol 9 (3) ◽  
pp. 344-352 ◽  
Author(s):  
L.I. Stefanovich ◽  
O.Y. Mazur ◽  
V.V. Sobolev

Introduction: Within the framework of the phenomenological theory of phase transitions of the second kind of Ginzburg-Landau, the kinetics of ordering of a rapidly quenched highly nonequilibrium domain structure is considered using the lithium tantalate and lithium niobate crystals as an example. Experimental: Using the statistical approach, evolution equations describing the formation of the domain structure under the influence of a high-frequency alternating electric field in the form of a standing wave were obtained. Numerical analysis has shown the possibility of forming thermodynamically stable mono- and polydomain structures. It turned out that the process of relaxation of the system to the state of thermodynamic equilibrium can proceed directly or with the formation of intermediate quasi-stationary polydomain asymmetric phases. Results: It is shown that the formation of Regular Domain Structures (RDS) is of a threshold character and occurs under the influence of an alternating electric field with an amplitude less than the critical value, whose value depends on the field frequency. The conditions for the formation of RDSs with a micrometer spatial scale were determined. Conclusion: As shown by numerical studies, the RDSs obtained retain their stability, i.e. do not disappear even after turning off the external electric field. Qualitative analysis using lithium niobate crystals as an example has shown the possibility of RDSs formation in high-frequency fields with small amplitude under resonance conditions


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.


2021 ◽  
Vol 51 (3) ◽  
pp. 738-745
Author(s):  
Minakshi Mandal ◽  
Rupali Maji ◽  
Sourangshu Mukhopadhyay

Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 242
Author(s):  
An-Chung Chiang ◽  
Yuan-Yao Lin ◽  
Shou-Tai Lin ◽  
Yen-Yin Lin

Electro-optic (EO) Bragg deflectors have been extensively used in a variety of applications. Recent developments show that bandwidths and deflection efficiencies, as well as angular bandwidths, would significantly limit the utilization of EO Bragg deflectors, especially for applications which need strong focusing, such as intra-cavity applications. In this paper, we introduce a broadband EO Bragg deflector based on periodically-poled lithium niobate with a monolithic dual-grating design. We analyzed the deflection properties of this device by using a modified coupled wave theory and showed that this device can be still efficient for a small beam radius under strong focusing, whereas a single-grating one becomes very inefficient. Using a 1064-nm laser beam with a 100-μm beam radius, we obtained a 74% deflection efficiency with a 190-V bias voltage with a 0.5-mm-thick and 7.5-mm-long dual-grating sample. The acceptance angle for the Bragg condition of this device is as large as a few tens of mrad. The potential bandwidth of this device exceeds 500 nm if the proper operation region is chosen.


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

2002 ◽  
Vol 743 ◽  
Author(s):  
W. Alan Doolittle ◽  
Gon Namkoong ◽  
Alexander Carver ◽  
Walter Henderson ◽  
Dieter Jundt ◽  
...  

ABSTRACTHerein, we discuss the use of a novel new substrate for III-Nitride epitaxy, Lithium Niobate. It is shown that Lithium Niobate (LN) has a smaller lattice mismatch to III-Nitrides than sapphire and can be used to control the polarity of III-Nitride films grown by plasma assisted molecular beam epitaxy. Results from initial growth studies are reported including using various nitridation/buffer conditions along with structural and optical characterization. Comparisons of data obtained from GaN and AlN buffer layers are offered and details of the film adhesion dependence on buffer layer conditions is presented. Lateral polarization heterostructures grown on periodically poled LN are also demonstrated. While work is still required to establish the limits of the methods proposed herein, these initial studies offer the promise for mixing III-Nitride semiconductor materials with lithium niobate allowing wide bandgap semiconductors to utilize the acoustic, pyroelectric/ferroelectric, electro-optic, and nonlinear optical properties of this new substrate material as well as the ability to engineer various polarization structures for future devices.


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