Filter-free miniaturized polarization-sensitive photodetectors have important applications in the next-generation on-chip polarimeters. However, their polarization sensitivity is thus far limited by the intrinsic low diattenuation and inefficient photon-to-electron conversion. Here, we implement experimentally a miniaturized detector based on one-dimensional tellurium nanoribbon, which can significantly improve the photothermoelectric responses by translating the polarization-sensitive absorption into a large temperature gradient together with the finite-size effect of a perfect plasmonic absorber. Our devices exhibit a zero-bias responsivity of 410 V/W and an ultrahigh polarization ratio (2.5 × 104), as well as a peak polarization angle sensitivity of 7.10 V/W•degree, which is one order of magnitude higher than those reported in the literature. Full linear polarimetry detection is also achieved with the proposed device in a simple geometrical configuration. Polarization-coded communication and optical strain measurement are demonstrated showing the great potential of the proposed devices. Our work presents a feasible solution for miniaturized room-temperature infrared photodetectors with ultrahigh polarization sensitivity.

Laser emission imaging is an emerging technology, which offers immense potential for revealing biological behavior with enhanced light‐matter interactions and signal contrast. State‐of‐the‐art lasers mostly provide physical information of cells, without being able to perform various biochemical functions or biological information of cell. Here this need is addressed by introducing hybrid liquid crystal microlaser resonators, an approach for label‐free laser emission imaging of secreted molecules associated with various types of cell–environment interaction. Liquid crystal microdroplets are designed as signal amplifiers to report subtle molecular events sandwiched in a Fabry–Pérot microcavity. Through the integration with a galvometer scanner, dynamic information of cell physiological processes is recorded through different lasing wavelengths. The capability of detecting small molecule, redox oxygen species, to larger molecules such as overexpressed proteins is demonstrated by using pancreatic cancer cell line. The capability of monitoring cell responses to anticancer drug is also illustrated. The proposed concept can be extended to multiplexed biolasers for investigating cell signaling, cell–cell interactions, and drug screening.

One of the most exciting breakthroughs in physics is the concept of topology that was recently introduced to photonics, achieving robust functionalities, as manifested in the recently demonstrated topological lasers. However, so far almost all attention was focused on lasing from topological edge states. Bulk bands that reflect the topological bulk-edge correspondence have been largely missed. Here, we demonstrate an electrically pumped topological bulk quantum cascade laser (QCL) operating in the terahertz (THz) frequency range. In addition to the band-inversion induced in-plane reflection due to topological nontrivial cavity surrounded by a trivial domain, we further illustrate the band edges of such topological bulk lasers are recognized as the bound states in the continuum (BICs) due to their nonradiative characteristics and robust topological polarization charges in the momentum space. Therefore, the lasing modes show both in-plane and out-of-plane tight confinements in a compact laser cavity (lateral size ~3λlaser). Experimentally, we realize a miniaturized THz QCL that shows single-mode lasing with a side-mode suppression ratio (SMSR) around 20 dB. We also observe a cylindrical vector beam for the far-field emission, which is evidence for topological bulk BIC lasers. Our demonstration on miniaturization of single-mode beam-engineered THz lasers is promising for many applications including imaging, sensing, and communications.

Carbon nanotubes (CNTs) possess extremely anisotropic electronic, thermal, and optical properties owing to their one‐dimensional character. While their linear optical properties have been extensively studied, nonlinear optical processes, such as harmonic generation for frequency conversion, remain largely unexplored in CNTs, particularly in macroscopic CNT assemblies. In this work, w e synthesized macroscopic films of aligned and type‐separated (semiconducting and metallic) CNTs and studied polarization‐dependent third‐harmonic generation (THG) from the films with fundamental wavelengths ranging from 1.5 to 2.5 μm. Both films exhibited strongly wavelength‐dependent, intense THG signals, enhanced through exciton resonances, and w e found third‐order nonlinear optical susceptibilities of 2.50 × 10−19 m2/V2 (semiconducting CNTs) and 1.23 × 10−19 m2/V2 (metallic CNTs), respectively, for 1.8 μm excitation. Further, through systematic polarization‐dependent THG measurements, w e determined the values of all elements of the susceptibility tensor, verifying the macroscopically one‐dimensional nature of the films. Finally, w e performed polarized THG imaging to demonstrate the nonlinear anisotropy in the large‐size CNT film with good alignment. These findings promise applications of aligned CNT films in mid‐infrared frequency conversion, nonlinear optical switching, polarized pulsed lasers, polarized long‐wave detection, and high‐performance anisotropic nonlinear photonic devices.This article is protected by copyright. All rights reserved

Whispering gallery mode polymer resonators are becoming competitive with devices made of other materials, however, the inherent thermal sensitivity of the materials and the small size limit their applications, such as high-precision optical gyroscope. Here, a method is proposed for fabricating large-scale NOA65 resonators with quality factors greater than 105 on a chip employing superoleophobic. The sandwich structure as the core layer of resonator is used to present the flexible remodeling characteristics, the surface roughness remains below 1 nm when the diameter changes by more than 25%. Importantly, theoretical and experimental results show that under the tuning action of external pressure, the equivalent thermal expansion coefficient of the resonator gradually approaches the glass sheet on both sides with the variation of 2 × 10−4 /°C∼0.9 × 10−4 /°C, and the corresponding temperature response range of 0.12 nm/°C∼−0.056 nm/°C shows the promise of temperature insensitivity resonators on a chip.