Lanthanide-based microlasers have attracted considerable attention owing to their large anti-Stokes shifts, multiple emission bands, and narrow linewidths

Lanthanide-based microlasers have attracted considerable attention owing to their large anti-Stokes shifts, multiple emission bands, and narrow linewidths. Various applications of microlasers, such as optical communication, optical storage, and polarization imaging, require selecting the appropriate laser polarization mode and remote control of the laser properties. Here, we propose a unique plasmon-assisted method for the mode selection and remote control of microlasing using a lanthanide-based microcavity coupled with surface plasmon polaritons (SPPs) that propagate on a silver microplate. With this method, the transverse electrical (TE) mode of microlasers can be easily separated from the transverse magnetic (TM) mode. Because the SPPs excited on the silver microplate only support TM mode propagation, the reserved TE mode is resonance-enhanced in the microcavity and amplified by the local electromagnetic field. Meanwhile, lasing-mode splitting can be observed under the near-field excitation of SPPs due to the coherent coupling between the microcavity and mirror microcavity modes. Benefiting from the long-distance propagation characteristics of tens of micrometers of SPPs on a silver microplate, remote excitation and control of upconversion microlasing can also be realized. These plasmon-assisted polarization mode-optional and remote-controllable upconversion microlasers have promising prospects in on-chip optoelectronic devices, encrypted optical information transmission, and high-precision sensors.show less

Neurodegenerative diseases, such as Parkinson’s and Alzheimer’s diseases, affect the elderly worldwide and will become more prevalent as the global popula

Neurodegenerative diseases, such as Parkinson’s and Alzheimer’s diseases, affect the elderly worldwide and will become more prevalent as the global population ages. Neuroinflammation is a common characteristic of neurodegenerative diseases. By regulating the phenotypes of microglia, it is possible to suppress neuroinflammation and, in turn, help prevent neurodegenerative diseases. We report a noninvasive photonic approach to regulating microglia from overexcited M1/M2 to the resting M0 phenotype using a special near-infrared (NIR) light emitted by the SrGa₁₂O₁₉ : Cr^{3 +} phosphor. The absorbance and internal and external quantum efficiencies of the optimal Sr ( Ga_0.99Cr_0.01)12O₁₉ phosphor synthesized at 1400°C for 8 h using 1 % H₃BO₃ + 1 % AlF₃ as flux are 53.9 % , 99.2 % , and 53.5 % ; the output power and energy-conversion efficiency of the LED device packaged using the optimal SrGa₁₂O₁₉ : Cr^{3 +} phosphor driven at 20 mA reach unprecedentedly 19.69 mW and 37.58 % , respectively. The broadband emission of the NIR LED device covers the absorption peaks of cytochrome c oxidase well, and the NIR light can efficiently promote the proliferation of microglia, produce adenosine triphosphate (ATP), reverse overexcitation, alleviate and inhibit inflammation, and improve cell survival rate and activity, showing great prospects for photomedicine application.show less

A method of preparing panda-shaped photonic crystal fibers (PCFs) based on secondary drawing technology is proposed in this paper. The secondary drawing c

A method of preparing panda-shaped photonic crystal fibers (PCFs) based on secondary drawing technology is proposed in this paper. The secondary drawing can not only reduce fiber diameter but also reduce core size by adding a glass sleeve. Silver-filled and non-silver-filled panda PCFs are prepared. The two ends of silver-filled panda PCF are connected with a broadband light source and a spectrometer, respectively, and the surface plasmon resonance phenomenon is detected. The secondary drawing technology provides a meaningful reference for the preparation of PCF in the future, and the prepared silver-filled panda PCF can be prepared into an optical fiber filter.show less

Self-injection locking has emerged as a crucial technique for coherent optical sources, spanning from narrow linewidth lasers to the generation of localiz

Self-injection locking has emerged as a crucial technique for coherent optical sources, spanning from narrow linewidth lasers to the generation of localized microcombs. This technique involves key components, namely a laser diode and a high-quality cavity that induces narrow-band reflection back into the laser diode. However, in prior studies, the reflection mainly relied on the random intracavity Rayleigh backscattering, rendering it unpredictable and unsuitable for large-scale production and wide-band operation. In this work, we present a simple approach to achieve reliable intracavity reflection for self-injection locking to address this challenge by introducing a Sagnac loop into the cavity. This method guarantees robust reflection for every resonance within a wide operational band without compromising the quality factor or adding complexity to the fabrication process. As a proof of concept, we showcase the robust generation of narrow linewidth lasers and localized microcombs locked to different resonances within a normal-dispersion microcavity. Furthermore, the existence and generation of localized patterns in a normal-dispersion cavity with broadband forward–backward field coupling is first proved, as far as we know, both in simulation and in experiment. Our research offers a transformative approach to self-injection locking and holds great potential for large-scale production.show less