Researchers at the Beijing Institute of Technology developed a new type of sensor significantly more sensitive than existing exceptional point-based sensors. This was achieved by introducing long-range non-reciprocal couplings into the sensor design. The new sensor was successfully fabricated and demonstrated superior performance in detecting tiny physical quantities. The study was published in the National Science Review.
The long-range non-reciprocal couplings are shown in the top left. The sensing results compared with those based on exceptional point-based sensors are provided in the top right. The corresponding circuit realization for the reconstructed sensor is provided in the bottom left, and tiny quantities are detected in the bottom right. Image Credit: Science China Press
Dr. Xiangdong Zhang is the Principal Investigator of the study and is affiliated with the Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, and the Ministry of Education's Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements.
Dr. Tian Chen carried out the theoretical design and derivation, while Dr. Deyuan Zou carried out the experiments. The design included several innovative physical mechanisms to overcome the sensitivity of the current sensors.
Integrating the non-Hermitian exception point into the sensor design is a common approach to achieving high sensitivity. However, this sensitivity upper bound is constrained by the non-Hermitian degeneracy order. These days, it is a difficult to increase sensitivity beyond what an extraordinary point-based sensor can accomplish.
Under the direction of Zhang, the lab director, Chen, and Zou set out to see if it could surpass the limit of an extraordinary point-based scorer. Following a complex reconstruction around the EP, they discovered that the addition of long-range non-reciprocal couplings allowed the exceptional point sensor's sensitivity limit to be exceeded.
The team created those coupling strengths to follow a power-law relationship with chain length. With this structure, the reconstructed system's sensitivity around the sixth exceptional point was three orders of magnitude higher than that of the corresponding-order exceptional point-based sensor.
“This design is rather simple, yet the sensor effect is enough good,” Zhang said.
The researchers created the above-designed circuit sensors and provided experimental evidence of their higher sensitivity in detecting minute physical quantities. Initially, the capacitor's modest value was ascertained.
The rebuilt sensor can precisely monitor the capacitor's minimum charge of 1 pF. This sensor can then detect the displacement between two 75 × 200 mm electrode plates and precisely measure the 0.75 mm displacement variation.
These experimental results on the electric circuit illustrate the incredible performance in the detection of tiny physical quantities. This new design can be easily extended to chip-implemented circuit sensors. There are three main advantages in the implementation of the chip, the first thing is the easily configurable components in the realization, the second thing is the enormous reduction of the parasitic effect, and the third thing is the increased operating frequency.
Dr. Xiangdong Zhang, Principal Investigator, Beijing Institute of Technology
Zhang said, “In this way, considering the three main advantages above, the design in this work displays a feasible prospect to implement a novel ultrasensitive sensor on the chip.”
Sensors play a crucial role in modern society and are widely used in industries such as environmental monitoring, biomedical analysis, and wireless networks. The authors designed and fabricated integrated circuit sensors in this study to demonstrate a new reconstruction scheme. This advancement paves the way for developing highly sensitive sensors with broad applications across multiple fields.
Journal Reference:
Bailleul, A. M., et al. (2020) Evidence of proteins, chromosomes, and chemical markers of DNA in exceptionally preserved dinosaur cartilage. National Science Review. doi.org/10.1093/nsr/nwz206.