Absolute measurement of three-dimensional polarization direction using scanning nonlinear dielectric Microscopy

2004 ◽  
Vol 838 ◽  
Author(s):  
Yasuo Cho ◽  
Tomoyuki Sugihara ◽  
Hiroyuki Odagawa

ABSTRACTA technique for measuring the absolute value of the ferroelectric polarization angle using scanning nonlinear dielectric microscopy (SNDM) is proposed and demonstrated. Using the technique, periodically poled lithium niobate (PPLN) with three-dimensional domain structure is observed. The measured polarization angles agreed well with the actual polarization orientations, and allowed precise visualization of the microdomain structure in PPLN. Through this experiment, we confirmed that SNDM is a useful tool for the absolute evaluation of the three-dimensional polarization direction.

2002 ◽  
Vol 748 ◽  
Author(s):  
Hiroyuki Odagawa ◽  
Yasuo Cho

ABSTRACTA scanning nonlinear dielectric microscope (SNDM) probe, called theε311 -type probe, and a system to measure the ferroelectric polarization component parallel to the surface using rotating electric field have been developed. This is achieved by measuring the ferroelectric material's nonlinear dielectric constant ε311 instead of ε333, which is measured in conventional SNDM. Experimental result shows that we can successfully determine polarization component parallel to the surface. The SNDM system can measure polarization at any angle from the surface normal which is often of interest.


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.


1998 ◽  
Vol 07 (01) ◽  
pp. 61-71
Author(s):  
C. L. Tang ◽  
K. C. Burr ◽  
F. Sh. Ganikhanov

The recent development of periodically poled lithium niobate (PPLN) has led to a variety of highly efficient and compact all-solid-state nonlinear optical devices. Of particular interest are the optical parametric oscillators. We have most recently demonstrated for the first time a highly efficient broadly tunable femtosecond optical parametric oscillator (fs OPO) using PPLN. The threshold for oscillation of the PPLN fs OPO is remarkably low, on the order of 50 mW. As a result, it is now possible to use a diode-pumped and frequency-doubled Nd:YVO 4 laser, rather than an Ar-ion laser, as the pump source for the mode-locked Ti:sapphire laser for pumping the fs OPO. Such an OPO can operate from approximately 1 μm to 5.4 μm. Femtosecond sources have been used in a variety of experiments to study the dynamics of hot carriers in semiconductors. Because of the limited available wavelength range of earlier femtosecond sources, most such studies have been limited to electron dynamics in the conduction band of III–V compounds such as GaAs. With the extended tuning range of the recently developed fs OPO's, it is now possible to study a much wider variety of materials and transitions. We have recently obtained preliminary results on the ultrafast dynamics of holes in GaAs using two-wavelength tunable femtosecond spectroscopy, by pumping the valence-to-conduction band transition at approximately 800 nm and simultaneously probing the transitions between the split-off band and the perturbed heavy-hole band at approximately 3 μm. These recent results are summarized and discussed briefly.


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