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Abstract Photonics in the frequency range of 5–15 terahertz (THz) potentially open a new realm of quantum materials manipulation and biosensing. This range, sometimes called “the new terahertz gap”, is traditionally difficult to access due to prevalent phonon absorption bands in solids. Low‐loss phonon–polariton materials may realize sub‐wavelength, on‐chip photonic devices, but typically operate in mid‐infrared frequencies with narrow bandwidths and are difficult to manufacture on a large scale. Here, for the first time, quantum paraelectric SrTiO3enables broadband surface phonon–polaritonic devices in 7–13 THz. As a proof of concept, polarization‐independent field concentrators are designed and fabricated to locally enhance intense, multicycle THz pulses by a factor of 6 and increase the spectral intensity by over 90 times. The time‐resolved electric field inside the concentrators is experimentally measured by THz‐field‐induced second harmonic generation. Illuminated by a table‐top light source, the average field reaches 0.5 GV m−1over a large volume resolvable by far‐field optics. These results potentially enable scalable THz photonics with high breakdown fields made of various commercially available phonon–polariton crystals for studying driven phases in quantum materials and nonlinear molecular spectroscopy.
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Broadband THz Modulation via Solid‐State Organic Electrochemical Devices
Abstract The sub‐Terahertz and Terahertz bands play a critical role in next‐generation wireless communication and sensing technologies, thanks to the large amount of available bandwidth in this spectral regime. While long‐wavelength (microwave to mm‐Wave) and short‐wavelength (near‐infrared to ultraviolet) devices are well‐established and studied, the sub‐THz to THz regime remains relatively underexplored and underutilized. Traditional approaches used in the aforementioned spectral regions are more difficult to replicate in the THz band, leading to the need for the development of novel devices and structures that can manipulate THz radiation effectively. Herein a novel organic, solid‐state electrochemical device is presented, capable of achieving modulation depths of over 90% from ≈500 nm of a conducting polymer that switches conductivity over a large dynamic range upon application of an electronically controllable external bias. The stability of such devices under long‐term, repeated voltage switching, as well as continuous biasing at a single voltage, is also explored. Switching stabilities and long‐term bias stabilities are achieved over two days for both use cases. Additionally, both depletion mode (always “ON”) and accumulation mode (always “OFF”) operation are demonstrated. These results suggest applications of organic electrochemical THz modulators in large area and flexible implementations.
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- Award ID(s):
- 2145240
- PAR ID:
- 10570837
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 37
- Issue:
- 11
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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