Fiber Bragg gratings have attracted extensive attention and research in the field of fiber optic sensors due to their low cost, ease of processing and improvement, and excellent sensing performance. They have been applied in temperature sensing, gas concentration sensing, bending sensing, and other fields. By means of weak fiber doping, polymer fiber manufacturing, parallel distribution of gratings, and manufacturing of microstructured fiber gratings, functions such as phase shifting, temperature compensation, temperature insensitivity, ultra-high temperature sensing, and bio-absorbable materials can be achieved.
In recent years, devices replicating the modulating effect of lenses have emerged, some based on principles of diffraction, phase change, or metallic resonance. With the advent of metasurfaces, devices have been created that use sub-wavelength microstructures based on the generalized Snell's law to achieve continuous phase change and thus manipulate the THz wavefront. In this paper, we endeavor to utilize liquid crystals, based on the generalized Snell's law, designing a terahertz modulating element working on geometric phase, enabling it to function like a terahertz lens. The experimental results confirmed that our THz liquid crystal lens, designed based on geometric phase and stemming from the generalized Snell's law, possesses sufficient modulation effect, demonstrating the feasibility of liquid crystal modulation in the THz frequency range.
Metasurfaces, as artificial materials, exhibit unique characteristics that are distinct from those found in natural materials. These properties, such as the negative refractive index and the inverse Doppler effect, ushered in new possibilities for a wide range of applications, particularly in the field of filtering, absorbing, and other communication devices. This paper introduces a novel approach for creating an electronically controlled tunable terahertz absorber based on liquid crystal and metasurfaces. The ability to modify the equivalent dielectric constant in the liquid crystal layer by leveraging the external electrical field enables the adjustment and control of the terahertz reflected waves. Under the bias saturated state, the liquid crystal molecules in the proposed tunable terahertz absorber align vertically, leading to a specific absorption peak at a frequency of 0.79 THz, with an absorption value of 0.86. However, under the bias off state, the liquid crystal molecules reorient themselves horizontally, with the absorption peaks dropping to two smaller peaks. The utilization of adjustable all-dielectric metasurfaces based on liquid crystal characteristics presents a promising solution that aligns with the demands of contemporary development. These metasurfaces offer versatility across a wide range of frequencies, spanning from microwave to infrared light. This adaptability enables their application in various fields and devices, introducing novel preparation and adjustment methods.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.