Arithmetic logic unit based on the metastructure with coherent absorption: erratum.

We present a corrigendum to our Letter [Opt. Lett.48, 5699 (2023)10.1364/OL.505761]. In section 3 of the original supplementary material, the absolute value is incorrectly taken in resolving the Kubo formula for describing the conductivity of graphene. Because this is a mistake with the conductivity of graphene, the coupling of the original structure is broken when the correct result is inserted into the code of the transfer matrix. So, the structure of the arithmetic logic unit (ALU), characteristic frequency point, and phase control have been modified accordingly. However, the ultimate function and the conclusion of this work remain unchanged.

A multiple cancer cell optical biosensing metastructure realized by CPA.

A one-dimensional optical biosensing metastructure (OBM) with graphene layers is presented in this paper. It is realized by coherent perfect absorption (CPA) and operates in the transverse electric mode. It shows a strong linear fitting relationship between the refractive index (RI) of the analysis layer and the frequency corresponding to the absorption peak, and the R-square is up to 1. Additionally, based on the principle of CPA, the OBM can realize the function of multiple cancer cell detection by adjusting the detection range by controlling the phase difference of coherent electromagnetic waves. Its detection ranges are 1.34-1.355 and 1.658-1.662. Thanks to its high-quality factor, great figure of merit, and low detection limit, whose best values are, respectively, 6.9 × 104, 1.2 × 104 RIU-1, and 3.6 × 10-6 RIU, the detection of weak changes in the RI of a cancer cell is possible. Additionally, its sensitivity can reach 26.57 THz RIU-1. This OBM based on CPA has major implications for advancing the study and investigation into the application of CPA. It also provides a simple and efficient approach to distinguish cancer cells and may be widely used in the biomedical field.

Arithmetic logic unit based on the metastructure with coherent absorption.

An arithmetic logic unit (ALU) based on the metastructure (MS) with coherent absorption (CA) is proposed in this Letter. The ALU can perform AND and exclusive OR logical operations at the same frequency point. So it can be regarded as an optical half-adder. By controlling the chemical potential of graphene and the phase difference of coherent electromagnetic waves (EWs), two different binary numbers are input into the ALU. The dynamic absorption peaks, which are generated based on the CA, output the outcomes of the carry-digit bit and non-carry sum bit. This ALU can be used in the field of optical processing and encryption, such as processing hamming code. This given ALU based on the MS with CA has major implications for advancing the study and investigation into the application of CA. Furthermore, it also provides a new, to the best of our knowledge, idea for the study of MS with logical operation.

Advanced optical terahertz fingerprint sensor based on coherent perfect absorption.

An advanced optical terahertz (THz) fingerprint sensor based on coherent perfect absorption (CPA) is proposed. Based on a one-dimensional layered photonic structure, the sensor contains a cavity that is developed for THz fingerprint measurement. Utilizing the magneto-optical effect of magnetized InSb, CPA is excited in the structure of the sensor. Taking α-lactose as exemplar material, this numerical simulation is integrated with a Drude-Lorentz model. The transfer matrix method (TMM) is used to calculate the sensitivity (S), linear range (LR), quality (Q), the figure of merit (FOM*), and detection limit (DL) theoretically. Employing the amplitude modulation detection method, the qualitative and quantitative analysis of the α-lactose thickness of 0-0.5 µm could be realized. Because of the fragility of CPA, the S is 0.78255 µm-1, the value of average Q is up to 8019.2, the value of average FOM* is 13 234.4 (THz µm)-1, and the lower DL is 4.21 × 10-6. Moreover, the evolutions of ensemble-averaged absorption in the vicinity of the absorption peaks for different types of disorder effects are considered, which will be considered in the fabrication of sensors.

Tunable and controllable multi-channel time-comb absorber based on continuous photonic time crystals.

To date there have been many studies on multi-channel absorbers for conventional photonic crystals (PCs). However, the number of absorption channels is small and uncontrollable, which cannot satisfy applications such as multispectral or quantitative narrowband selective filters. To address these issues, a tunable and controllable multi-channel time-comb absorber (TCA) based on continuous photonic time crystals (PTCs), is theoretically proposed. Compared with conventional PCs with fixed refractive index (RI), this system forms a stronger local electric field enhancement in the TCA by absorbing externally modulated energy, resulting in sharp multi-channel absorption peaks (APs). Tunability can be achieved by adjusting the RI, angle, and time period unit (T) of the PTCs. Diversified tunable methods allow the TCA to have more potential applications. In addition, changing T can adjust the number of multi-channels. More importantly, changing the primary term coefficient of n1(t) of PTC1 can control the number of time-comb absorption peaks (TCAPs) in multi-channels within a certain range, and the mathematical relationship between the coefficients and the number of multiple channels is summarized. This will have potential applications in the design of quantitative narrowband selective filters, thermal radiation detectors, optical detection instruments, etc.