## 1 Introduction
Although the beam after a deflection in an EO steerer can be expanded in a telescope, that will decrease the deflection angle proportional to that beam magnification as follows [11]:  
\[\theta_{2}=\frac{\theta_{1}}{M} \tag{1}\]  
where \(\theta_{2}\) is the deflection angle after expansion by the factor of \(M\), and \(\theta_{1}\) is the deflection angle before beam expansion. Therefore, deflecting an 80 um beam to 125 mrad is equivalent to deflecting a 6 mm beam to 1.67 mrad. The factor that remains constant is sometimes called an angle/aperture product [3]. Instead of the deflection angle, which is not a complete metric for beam steerers, we describe the number of the resolvable spots instead as the metric for light beam steerers as follows [1]:  
\[N=\frac{\theta}{\theta_{beam}} \tag{2}\] \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Material** & \(n\) & \(\varepsilon\) & \(r\) (pmV\({}^{-1}\)) & \(n^{3}r\)/\(\varepsilon\) (pmV\({}^{-1}\)) \\ \hline \multicolumn{5}{c}{**Ferroelectrics**} \\ \hline LiNbO\({}_{3}\) & 2.26 & 29 & 31 & 12.339 \\ LiTaO\({}_{3}\) & 2.23 & 43 & 31 & 7.995 \\ KNbO\({}_{3}\) & 2.23 & 55 & 64 & 12.904 \\ BaTiO\({}_{3}\) & 2.4 & 1800 & 1670 & 12.826 \\ SBN75 (Sr\({}_{0.75}\)Ba\({}_{0.25}\)Nb\({}_{2}\)O\({}_{6}\)) & 2.3 & 1550 & 1340 & 10.519 \\ SBN60 (Sr\({}_{0.86}\)Ba\({}_{0.48}\)Nb\({}_{2}\)O\({}_{6}\)) & 2.3 & 750 & 216 & 3.504 \\ Ferroelectric KTN (KTaO\({}_{3.53}\)Nb\({}_{0.65}\)O\({}_{3}\)) & 2.3 & 10,000 & 8000 & 9.734 \\ KBN (K\({}_{2}\)BiNb\({}_{5}\)O\({}_{15}\)) & 2.4 & 510 & 346 & 9.379 \\ KBN (K\({}_{2}\)BiNb\({}_{5}\)O\({}_{15}\)) Ce\({}^{3+}\)Ce\({}^{4+}\) & 2.4 & 509 & 370 & 10.049 \\ BSTN & 2.4 & 345 & 200 & 8.014 \\ BSKNN-2 & 2.35 & 800 & 380 & 6.164 \\ BSKNN-3 & 2.301 & 800 & 420 & 6.396 \\ SCNN & 2.321 & 1740 & 1200 & 8.623 \\ BBO (BaB\({}_{2}\)O\({}_{4}\)) & 1.67 & 6.7 & 2.7 & 1.877 \\ \multicolumn{5}{c}{**Semiconductors**} \\ GaAs & 3.5 & 13.2 & 1.2 & 3.898 \\ InP & 3.29 & 12.6 & 1.45 & 4.098 \\ CdTe & 2.82 & 9.4 & 6.8 & 16.223 \\ Bi\({}_{12}\)SiO\({}_{20}\) & 2.54 & 56 & 5 & 1.463 \\ Bi\({}_{12}\)GeO\({}_{20}\) & 2.55 & 47 & 3.4 & 1.200 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The properties of some materials with linear electro-optic (EO) response. where \(\theta\) is the deflection angle depending on the geometry, optical, crystallography properties of the crystal, the type of EO effect, and the strength of the external electric field, and \(\theta_{beam}\) is the beam divergence angle in far-field, which is calculated as [1]  
\[\theta_{beam}=\frac{\lambda}{\pi w_{0}} \tag{3}\]  
where \(\lambda\) is the wavelength of the light, and \(w_{0}\) is the radius of the beam, which can usually be up to half of the crystal height (H) or width (W) as  
\[Max\ w_{0}=0.5\times\text{Min}\{\text{W},\text{H}\} \tag{4}\]  
The first EO steerer was introduced by [PERSON] et al. in 1964 using KH\({}_{2}\)PO\({}_{4}\) as the EO crystal [21]. This crystal is paraelectric with tetragonal symmetry at room temperature. Although its Curie temperature is below \(-150\)\({}^{\circ}\)C, which makes its optical properties almost temperature-independent, this crystal is soluble in the water. In addition, a very large voltage should be applied to provide enough phase delay, making it impractical. [PERSON] et al. employed potassium tantalate niobate as a single EO crystal in their EO scanners [22]. The most used single crystal in EO steerers is LiTaO\({}_{3}\). [PERSON] et al., [PERSON] et al., [PERSON] et al., and many more used LiTaO\({}_{3}\) in their EO scanners [12; 13; 17; 20; 23; 24]. Because both of those two crystals are single ferroelectric crystals, their dipole orientations must be adjusted by applying more than 21 kV/mm voltage. In addition, multiple prism-shaped domains must be created to steer a small beam to a few degrees by applying more than 14 kV/mm on the crystal. Furthermore, those crystals are temperature-dependent [5; 15], and their EO scanners were polarization-dependent.