Abstract:Due to its distinctive traits such as low energy consumption， high transmittance， potent anti-interference capacity， fingerprint， THz flexible regulation assumes a crucial role in detection， imaging， radar， and military defense， and has garnered significant attention from scholars both domestically and internationally in recent years. Nevertheless， high costs and losses remain significant factors restricting the advancement of terahertz regulation. Perovskite materials possess outstanding photoelectric properties， a straightforward preparation process， the capacity for mass production， and thereby become one of the most promising materials for the fabrication of terahertz detectors. Additionally， the facile tunability of perovskite compensates for the difficulty in adjusting the metasurface and meets the requirement for tunable metasurface. The combination of the two enables effective regulation of terahertz in the light field. In this paper， we have designed two types of coded metasurface composed of organic-inorganic hybrid perovskite CH₃NH₃PbI₃， polyimide， and aluminum， and manipulated the operating frequencies of the two structures through light field control. The results were compared with theoretical calculations to verify the effect. The first structure can be controlled by the light field to select between a broadband operating frequency and high efficiency. The second structure functions only at 0.1THz and can vary the phase through light， thereby reversing the phase of the original structure to control the direction of beam reflection. On this basis， we fabricated the device and verified it. To a certain extent， this paper fills the void in the field of optical field regulation of coded metasurface and offers a train of thought for subsequent research.

Abstract:To avoid the accumulation of estimation errors from explicitly aligning multi-frame features in current infrared small-dim target detection algorithms， and to alleviate the loss of target features due to network downsampling， a progressive spatio-temporal feature fusion network is proposed. The network utilizes a progressive temporal feature accumulation module to implicitly aggregate multi-frame information and utilizes a multi-scale spatial feature fusion module to enhance the interaction between shallow detail features and deep semantic features. Due to the scarcity of multi-frame infrared dim target datasets， a highly realistic semi-synthetic dataset is constructed. Compared to the mainstream algorithms， the proposed algorithm improves the probability of detection by 4.69% and 4.22% on the proposed dataset and the public dataset， respectively.

Abstract:The master oscillator power amplifier （MOPA） laser is receiving increasing attention due to its ability to achieve high power and beam quality output. In order to improve the polarization degree of MOPA laser and reduce the efficiency loss during polarization combining， InGaAs/AlGaAs compressive single quantum well was used in the active region. The optical confinement factor of TE-mode in ridge waveguide was improved by 1.35 μm deep etching， whereas the TE optical gain in tapered amplifier was increased through on-chip metal stress regulation. Combining the two schemes not only improves the degrees of polarization （DOP） of two sections， but also reduces the polarization angle difference. Finally， 11W@15A continuous output and over 90% DOP of the MOPA have been achieved by standard process fabrication.

Abstract:The three-dimensional perception of road objects in challenging environments is crucial for the development of autonomous vehicles that operating in all conditions， at all hours. Infrared binocular vision mimics the human binocular system， facilitating stereoscopic perception of objects in challenging conditions such as dim or zero-light environments. The core technology for stereoscopic perception in binocular vision systems is accurate object detection and matching. To streamline the complex sequence of object detection and matching procedures， a synchronous object detection and matching network （SODMNet） is proposed， which can perform synchronous detection and matching of infrared objects. SODMNet innovatively combines an object detection network with an object matching module， leveraging the deep features from the classification and regression branches as inputs for the object matching module. By concatenating these features with relative position encoding from the feature maps and processing the concatenated features through a convolutional network， the network generates feature descriptors for the left and right images. Object matching is then achieved by calculating the Euclidean distances between these descriptors， thus facilitating synchronous object detection and matching in binocular vision. In addition， a novel nighttime infrared binocular dataset， annotated with targets such as pedestrians and vehicles， is created to support the development and evaluation of the proposed network. Experimental results indicate that SODMNet achieves a significant improvement of more than 84.9% in object detection mean average precision （mAP） on this dataset， with an object matching average precision （AP） of 0.5777. These results demonstrate that SODMNet is capable of high-precision， synchronized object detection and matching in infrared binocular vision， marking a significant advancement in the field.

Abstract:This paper presents an innovative three-dimensional （3D） heterogeneously integrated photoreceiver， which is optimized for analog microwave optical links that demand both wide bandwidth and high input optical power. The key of this design is the uni-traveling-carrier photodiode （UTC-PD）， which has been flip-chip integrated onto a microwave integrated circuit submount. This integration approach enhances the photoreceiver"s bandwidth and high power handling capabilities. The material doping and epitaxial processes of the UTC photodiode were optimized to augment its power endurance. Meanwhile， the responsivity of the photodiode was improved through the adoption of an integrated back-illuminated lens complemented by the addition of a metallic reflective layer. By establishing a precise model of the photodiode， we have refined the bandwidth characteristic of the photoreceiver using impedance compensation and broadband matching circuit design techniques. Flip-chip bonding the photodiode chip onto the microwave integrated circuit chip has substantially mitigated the impact of interconnect circuits on high-frequency performance. Furthermore， the thermal conductivity and high-power resilience of the detector chip were enhanced via gold-tin alloy micro-bump interconnections and the design of a high thermal conductivity substrate layer. The three-dimensional heterogeneous integrated photoreceiver features a 1-dB bandwidth of 42 GHz， an RF return loss exceeding 11 dB， a responsivity surpassing 0.85 A/W， a dark current below 50 nA， and a saturated input optical power of over 120 mW.By leveraging the distinctive properties of the UTC-PD， our three-dimensional （3D） heterogeneous integrated photoreceiver design achieves superior efficiency and responsiveness， positioning it as a leading solution for cutting-edge microwave photonics applications.

Abstract:In the realm of optoelectronics， photodetectors play pivotal roles， with applications spanning from high-speed data communication to precise environmental sensing. Despite the advancements， conventional photodetectors grapple with challenges with response speed and dark current. In this study， we present a photodetector based on a lateral MoTe₂ p-n junction， defined by a semi-floating ferroelectric gate. The strong ferroelectric fields and the depletion region of the p-n junction in the device are notably compact， which diminish the carrier transit time， thereby enhancing the speed of the photoelectric response. The non-volatile MoTe₂ homojunction， under the influence of external gate voltage pulses， can alter the orientation of the intrinsic electric field within the junction. As a photovoltaic detector， it achieves an ultra-low dark current of 20 pA， and a fast photo response of 2 μs. The spectral response is extended to the shortwave infrared range at 1550 nm. Furthermore， a logic computing system with light/no light as binary input is designed to convert the current signal to the voltage output. This research not only underscores the versatility of 2D materials in the realm of sophisticated photodetector design but also heralds new avenues for their application in energy-efficient， high-performance optoelectronic devices.

Abstract:With the development of remote sensing technology， the detection sensitivity of infrared system is increasingly required. The infrared imaging detection technology based on linear avalanche device can effectively improve the detection sensitivity in high frame frequency applications. Based on the short-wave infrared linear avalanche detector assembly of 512×512， a small-aperture and lightweight infrared imaging system is designed and its performance is tested under low reverse bias. The test results show that the increase of SNR of the imaging system based on the linear avalanche infrared detector is basically linear with the multiplication factor M under short integration time， and the SNR of the system is 3 times that of the traditional camera of the same caliber.

Abstract:Dual-band thermal emitters with narrow bandwidths are important in various applications in the infrared field， such as in infrared sensing and infrared imaging. However， conditions for narrowband emission in different wavelengths can conflict with each other， making it difficult to achieve dual-band emitter. In this paper， a new type of lithography-free infrared dual-band thermal emitter is proposed， which consists of alternately deposited Ge and YbF₃ films on Al films. The narrowband emission characteristics stem from the Tamm plasmon polaritons （TPP） that can be excited by the distributed Bragg reflector and the Al substrate under certain conditions. The geometric parameters are optimized using multi-objective particle swarm optimization. The experiment results confirm that dual-band emitter can simultaneously exhibit narrowband emitter characteristics in both mid-wave infrared （MWIR） and long-wave infrared （LWIR） regions. The proposed method can be used in the design of multi-band emitssion modulation applications， which can be applied in the fields of multi-gas sensing and multi-band infrared camouflage.

Abstract:In this work， we investigate the impact of the whole small recess offset on DC and RF characteristics of InP high electron mobility transistors （HEMTs）. L_g = 80 nm HEMTs are fabricated with a double-recessed gate process. We focus on their DC and RF responses， including the maximum transconductance （g_{m_max}）， ON-resistance （R_ON）， current-gain cutoff frequency （f_T）， and maximum oscillation frequency （f_max）. The devices have almost same R_ON. The g_{m_max} improves as the whole small recess moves toward the source. However， a small gate to source capacitance （C_gs） and a small drain output conductance （g_ds） lead to the largest f_T， although the whole small gate recess moves toward the drain leads to the smaller g_{m_max}. According to the small-signal modeling， the device with the whole small recess toward drain exhibits an excellent RF characteristics， such as f_T = 372 GHz and f_max = 394 GHz. This result is achieved by paying attention to adjust resistive and capacitive parasitics， which play a key role in high-frequency response.

Abstract:Organic semiconductor materials have shown unique advantages in the development of optoelectronic devices due to their ease of preparation， low cost， lightweight， and flexibility. In this work， we explored the application of the organic semiconductor Y6-1O single crystal in photodetection devices. Firstly， Y6-1O single crystal material was prepared on a silicon substrate using solution droplet casting method. The optical properties of Y6-1O material were characterized by polarized optical microscopy， fluorescence spectroscopy， etc.， confirming its highly single crystalline performance and emission properties in the near-infrared region. Phototransistors based on Y6-1O materials with different thicknesses were then fabricated and tested. It was found that the devices exhibited good visible to near-infrared photoresponse， with the maximum photoresponse in the near-infrared region at 785 nm. The photocurrent on/off ratio reaches 10²， and photoresponsivity reaches 16 mA/W. It was also found that the spectral response of the device could be regulated by gate voltage as well as the material thickness， providing important conditions for optimizing the performance of near-infrared photodetectors. This study not only demonstrates the excellent performance of organic phototransistors based on Y6-1O single crystal material in near-infrared detection but also provides new ideas and directions for the future development of infrared detectors.