In the previous paper [1], the EO coefficients γ₃₃ and γ₁₃ of homogeneously Ti⁴⁺-doped LiNbO₃ crystals were measured by adopting two different voltage-applying schemes. In one scheme, here named scheme A for convenience, a DC voltage was applied to each crystal via a pair of external Cu slab electrodes (with a dimension of X × Y × Z = 40 mm × 50 mm × 0.5 mm). In another scheme, here named scheme B, a DC voltage was applied to the crystal through the 150 nm thick Al films coated onto two Z-surfaces of each crystal. In our previous paper, the γ₃₃ and γ₁₃ measured from the scheme A and B were considered as the unclamped and clamped coefficients, respectively. According to the definition, the EO coefficients as measured below and above the piezo-resonance are the unclamped (constant stress) and clamped (constant strain) coefficients, respectively [2]. This means that the EO coefficient measured by applying a low-frequency or DC modulation voltage is unclamped. Regarding our measurements, as a DC voltage was applied to the crystal in both cases of scheme A and B, no clamped coefficients were actually obtained, all the measured γ₁₃ and γ₃₃ are unclamped. Thus, the originally claimed clamped γ₁₃ and γ₃₃ [1], which were measured from the scheme B, should be corrected as “unclamped γ₁₃ and γ₃₃”. The correction to the mistake in [1] involves the related description throughout the whole paper, including the Abstract, Introduction, Experimental description, Results and discussion, Conclusion, and Fig. 3 as well. Figure 1 shows the corrected version of original Fig. 3 in [1].

 

Fig. 1 Unclamped (a) γ₃₃ and (b) γ₁₃ measured as a function of Ti⁴⁺ doping concentration for two voltage-applying schemes A (green balls) and B (red balls).

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In addition, the acknowledgment part is modified by appending “and by Overseas, Hong Kong & Macao Scholars Cooperative Researching Fund of NSFC.” The corrected acknowledgments are below.