Electric-field-controlled optical switch using Kerr effect and gradient of the composition ratio Nb/(Ta + Nb)

• An abnormal laser deflection phenomenon in KTN crystals is demonstrated.
• The origin of the deflection phenomenon was discussed in detail.
• By exploiting the deflection, we have designed an optical switch.
• The g11/g12 ratio (>10), wavelength range(491–1064 nm), and I–V characteristics (0–800 V) were studied.
• The extinction ratio (0–1) and influence of the photorefractive effect were studied.

By exploiting the Kerr effect and the gradient of the composition ratio m, Nb/(Ta + Nb) in mol%, in KTa1−xNbxO3 (KTN) crystals, we have designed an electric-field-controlled optical switch. The operating principle of the switch is described. During the switching process, the incident linearly polarized beam is orthogonally deflected as it propagates through the crystals. The g11/g12 ratio (>10), wavelength range (491–1064 nm), I–V characteristics (0–800 V), extinction ratio (0–1), gradient of Curie temperature (21–22.9 °C), response time that may be in ns order, and influence of the photorefractive effect were studied. The results show that our design provides a new kind of optical switch with macro scale (mm order), adjustable extinction ratio (0–1), wide wavelength range (491–1064 nm).

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