Ultrahigh Modulation Enhancement in All-Optical Si-Based THz Modulators Integrated with Gold Nanobipyramids

Abstract

Optical regulation strategy with the aid of hybrid materials can significantly optimize the performance of terahertz devices. Gold nanobipyramids (AuNBPs) with synthetical tunability to the near-infrared band show strong local field enhancement, which improves optical coupling at the interface and benefits the modulation performance. We design AuNBPs-integrated terahertz modulators with multiple structured surfaces and demonstrate that introducing AuNBPs can effectively enhance their modulation depths. In particular, an ultrahigh modulation enhancement of 1 order of magnitude can be achieved in the AuNBPs hybrid metamaterials accompanied by the multifunctional modulation characteristics. By application of the coupled Lorentz oscillator model, the theoretical calculation suggests that the optical regulation with AuNBPs originates from increased damping rate and higher coupling coefficient under pump excitation. Additionally, a terahertz spatial light modulator is constructed to demonstrate multiple imaging display and consume extremely low power, which is promising for the potential application in spatial and frequency selective imaging.

Highly localized, efficient, and rapid photothermal therapy using gold nanobipyramids for liver cancer cells triggered by femtosecond laser

“…For some photothermal tumor treatment methods, such as laser tumor ablation technology, the goal of this technology is to rapidly increase the temperature of the tumor target 22 , 23 . In addition, it is always expected to achieve the goal of local in situ inactivation of the tumor to avoid damage to normal tissues such as blood vessels near the tumor.…”

Microtopography‐Guided Double‐Layer Cross Structure for a Terahertz Multiband Amplitude Modulator

“…[4][5][6] THz modulator is a kind of THz device, which can be used to modulate the amplitude or frequency of THz waves by physical means (e.g., temperature and electricity). [7][8][9][10] Vanadium dioxide (VO 2 ) is a kind of metal oxide with phase transition, [11] and the non-metallic state of VO 2 changes to metallic state after temperature rises to 68 °C, which can lead modulator with a double-layer cross structure was designed and fabricated, which can realize a multiband amplitude modulation in 1-2 THz. A microtopographic substrate-guided method was proposed to fabricate the modulator with low-cost and high accuracy capacities.…”

“…[ 4–6 ] THz modulator is a kind of THz device, which can be used to modulate the amplitude or frequency of THz waves by physical means (e.g., temperature and electricity). [ 7–10 ] Vanadium dioxide (VO 2 ) is a kind of metal oxide with phase transition, [ 11 ] and the non‐metallic state of VO 2 changes to metallic state after temperature rises to 68 °C, which can lead electromagnetic waves change from transmission to reflection, and the change process is reversible. Due to the phase change properties, VO 2 is often embedded in a metamaterial structure to fabricate a THz modulator, and other materials which have the same phase change properties (e.g., bismuth, graphene, and gyroelectric) can be used to fabricate the THz modulator too.…”

Active and Smart Terahertz Electro-Optic Modulator Based on VO2 Structure

“…The terahertz (THz) technology, for its promising applications in the fields of imaging, communication, medicine, and security, has attracted considerable attention recently. These applications drive urgent needs for THz devices such as modulators, − lenses, polarizers, and absorbers. , Among them, THz modulators play an important role in THz imaging and next-generation wireless communication systems. Aiming at different application aspects, many attempts have been performed over the past decades to develop not only transmission but also reflection modulators, and not only passive but also active ones .…”