Tunable band elimination filter based on photonic crystals

Abstract

The invention discloses a tunable band elimination filter based on photonic crystals, which is mainly formed by periodically arranging two materials with different refractive indexes, namely a dielectric layer and a phase change layer, and mutually overlapping and combining the two materials, and the structural sizes of the same dielectric are completely the same. The principle of the filter is asfollows: when electromagnetic waves are vertically incident along the positive direction of the Z axis, the electromagnetic waves can be reflected and refracted for many times at the laminated interface, so that a very smooth and approximately horizontal stop band, namely a photonic forbidden band, is formed. On the basis of the photonic crystal, a phase change medium is used, so that the photonic band gap of the photonic crystal is subjected to blue shift. The filter has the biggest advantage that the dynamic tuning of the electromagnetic characteristics of the device can be realized. The stop-band filter is easy to manufacture and low in cost, and has an extremely good stop-band filtering effect.

Description

technical field [0001] The invention relates to the field of electromagnetic wave filtering characteristics in the terahertz band, in particular to a tunable band-stop filter based on photonic crystals. Background technique [0002] In recent years, great attention has been paid to innovative strategies for developing devices with stable optical properties. However, with the deepening of the application of nanophotonic devices and optoelectronic devices, in terms of integrated photonic chips, optical interconnects and even photonic integrated circuits, the optical characteristics of solid-state have been out of touch with practical applications. This requires the introduction of active features into the device to increase the flexibility of dynamic adjustment, so more and more researchers have begun to pay attention to the tunable characteristics of the device. [0003] The concept of photonic crystal was proposed by S.John and E.Yablonovitch respectively in 1987, and it ha...

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Problems solved by technology

However, these schemes are difficult to achieve effective active tuning

[0005] For example, the material used in the article (Ahmed, Shaban, & Aly, 2017) is lithium niobate (LN). When it is connected to the electrode, although it can also achieve the tuning function, it uses an ultra-high bias voltage, which is in In practical application, it is a difficult problem

Another example is that the material used in the article (Phys et al., 2017) is liquid crystal. When this device is connected to electrodes, it can also achieve better tuning function, but the most important point is that the design and manufacture of liquid crystal-based layers face high Complexity and difficulty in integrating, which is against the direction of future development

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