Abstract
We have successfully fabricated two types of optical switch devices, namely, all-optical switch (VO
/quartz) and electro-optical switch (VO
/TiO
/ITO/glass) based on semiconductor-to-metallic phase transition characteristic of vanadium dioxide (VO
) smart coatings. The VO
active layer, the TiO
buffer layer, and the ITO transparent conductive electrode used in these devices, were achieved by reactive pulsed laser deposition. The optical switching of the fabricated devices was investigated at = 1.55 m. The semiconductor (on) to metallic (off) phase transition was controlled by photoexcitation of VO
in the case of the all-optical switch, and by an external electric-field between the ITO and the VO
layer in the case of the electro-optical switch. The extinction ratio (on/off) is found to be much higher for the all-optical switch than for the electro-optical switch. For the all-optical switch, extinction ratio of about 22 dB and 12 dB are obtained in the transmission and reflection modes respectively. In the case of the electro-optical switch, the extinction ratio is about 12 dB in the transmission mode and 5 dB in the reflection mode.