Wang Xin,Zhao Haiyan,Li Angzhen,Tian Ke,Brambilla Gilberto,Wang Pengfei
In this letter, an Nd3+-doped compound fluorosilicate glass was successfully fabricated with the method of melt-quenching. Under the excitation of a 808 nm laser, enhanced near-infrared photoluminescence emission at the range from 1,065 to 1,140 nm was observed in the glass sample. To characterize its stability and resistance to environmental effects, transmission spectra at the range of NIR-MIR were measured under different environments, including humidity and temperature. In addition, the obtained fluorosilicate glass was also developed as a microsphere resonator by using CO2 laser heating method. When the diameter of the microsphere was controlled at 61.5 μm, coupling with a tapered fiber, single-multimode lasing in the wavelength range λ1,056–1,071 nm was achieved with a low lasing threshold of 1.5 mW. Compared to silica and phosphate glasses, this fluorosilicate glasses have lower phonon energy, which can reduce the probability of non-radiative transitions and improve the photoluminescence efficiency. Therefore, using it as the raw material, the developed microsphere resonator offers a high transition temperature and with a low lasing threshold, which are promising it for high performance sensing and detection applications.
Chun Zhou,Jie Yu,Hongxing Dong,Fanglong Yuan,Xiaopeng Zheng,Mingming Jiang,Long Zhang
Perovskite colloidal quantum dots (CQDs) enable a solution-processed approach toward lasers, simultaneously providing tunable wavelength, high quantum efficiency, large absorption cross-section, and long Auger lifetimes. However, broad-band single-mode lasers based on such CQDs have been proven to be challenging. Here we report broad-band single-mode lasers from solution-processed CsPbX3 (X = Cl, Br, I) CQDs based on a high-quality zinc oxide microrod hexagonal whispering-gallery microcavity. A typical single-mode laser with ultra-narrow linewidth (∼0.21 nm, quality factor ∼3000) at 11.7 μJ cm−2 was obtained at 636 nm based on the conformal deposition of CsPb(Br0.5I0.5)3 CQDs on an individual hexagonal zinc oxide microrod cavity with a radius of about ∼776 nm. Moreover, by tuning the halogen ratio, synthesis temperature and the size of the zinc oxide microrods, broad-band tunable single-mode lasers are obtained across the entire visible spectrum from 417 nm to 723 nm. These results represent a significant step towards easy solution-processed broad-band tunable single-mode lasers.
Dynamic modulation of microcavity lasers is crucial for achieving stable single-mode operation with high monochromaticity, compact footprint, and directional emission. However, the emergence of higher-order transverse modes with increasing cavity dimensions has frustrated efforts to scale up cavities while maintaining stable single-mode operation. To date, no suitable physical mechanism has been identified that enables cavity size-independent single-mode lasing. Herein, a breakthrough non-invasive technique is developed for in situ engineering of natural nano-grooves in large-size ( ≥ $ \ge $ 20 × 20 µm) perovskite microplates (MPs) through kinetically controlled vapor-phase epitaxy, achieving unprecedentedly precise mode control for optimal single-mode lasing performance. Critically, these well-defined grooves can alter the lasing resonance modes within the microlasers, enabling the transition from whispering gallery mode (WGM) to Fabry-Pérot (F-P) mode. The optical anisotropy induced by engineered groove structures also achieves polarized lasing emission with a high degree of polarization approaching 0.65. Additionally, numerical simulations elucidate that the external-cavity-free, high-quality (≈2660), and single-mode F-P lasing behavior under large-size conditions arises from the coupling of multiple cleavage cavities, which is induced by broken grooves in perovskite MPs morphology. This study pioneers a mode-selective modulation approach that enables scalable polarization engineering in large-area single-mode microlasers, fundamentally advancing multifunctional integration in photonics and high-density optoelectronic systems.
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