The high-precision patterning of metal halide perovskites (MHPs) is of paramount importance for their device application. Here, we demonstrate the femtosecond (fs)-laserassisted formation of three-dimensional MHP nanocrystal (NC) patterns with strong blue photoluminescence (PL) inside an oxide glass. Our strategy enables the crystallization and erasing of CsPb(Cl/Br) 3 NCs inside a glass localized around the laser focal area through a combination of fs laser irradiation and thermal treatment processes. These recoverable patterns exhibit a switchable PL associated with the laser-induced defect and the thermal healing of MHP NCs that are benefits from the soft ionic crystal structure and low formation energy of the MHPs. Due to the high stability offered by the protection of the oxide glass matrix, the laser printing of fine-structured MHP micropatterns can be repeated over multiple cycles with a high robustness compared with their colloidal process counterparts. Our results demonstrate a simple strategy for creating emissive patterns inside a stable and transparent solid matrix that could be promising for applications including information storage, three-dimensional displays, anticounterfeit labels, and information security protection.

of photons near a circular ring boundary via successive total internal reflections, whispering gallery mode microcavities exhibit ultrahigh Q factors and extremely small mode volumes, leading to greatly enhanced light-matter interactions. [2][3][4] These superior characteristics make WGM microcavities highly attractive for on-chip optical communications, including microlaser sources, [5,6] active filters, [7] optical sensors, [8,9] and others. Using WGM microcavities as resonant cavities for laser oscillations, the light energy density in microcavities is quite high, which results in the reduction of laser thresholds down to the microwatt range. [10][11][12] With an extremely high quality factor and facile processability, inorganic glasses are the most reliable materials for building WGM lasers. In the 1990s, near-infrared lasers were demonstrated in Nd 3+ -doped glass microspheres. [12] Since then, using amorphous glass microcavities to generate lasers with RE-ions has been well established. [11,[13][14][15] Furthermore, various kinds of lasers, such as Raman lasers [16] and second harmonics, [17,18] have been developed by applying glass WGM resonators. However, unlike crystals, glasses are amorphous, and they are characterized by relatively large phonon energy and broad phonon energy distribution, which are detrimental to the luminescence of rare earth (RE) ions that serve as the emission centers. Combining the low phonon energy of the crystalline phase with the excellent mechanical and chemical stability of the oxide matrix, the oxyfluoride nanocrystallized glass ceramic (NGC) has been regarded as an ideal host material for RE ions. [19] However, WGM laser output from NGC microcavities has not yet been reported. The main reason is that the absorption and scattering loss increase rapidly with the growth of nanocrystals in the glass matrix, resulting in the reduction of cavity Q factors that hinders low threshold laser output. To address these obstacles, we carefully designed an excellent oxyfluoride NGC material, where NaYF 4 nanocrystals are crystallized within the borosilicate glass matrix through a controlled heat-treatment process.Since the refractive index of the nanocrystal matches well with the glass matrix, and the sizes of the precipitated nanocrystals are small and uniform, the rise in absorption and scattering losses, which are very harmful to Q factors, are prevented. As a result, Er 3+ -doped NGC microsphere cavities with Q factors as high as 10 6 are obtained, which enables single mode WGM Nanocrystallized glass ceramics (NGCs) are important optical materials, but few studies have focused on their laser actions. Here, by precipitation of NaYF 4 nanocrystals enriched with Er 3+ ions in an oxide glass matrix, great enhancement of the luminescence properties for the NGC microspheres is realized. By carefully matching the refractive index of the glass matrix with that of the NaYF 4 nanocrystals and controlling the size and distribution of the precipitated nanocrystals, the absorption and Rayleigh scat...

With the wide use of micro-nano photonic devices in on-chip optical communication, physical and chemical sensing, organic microlasers have gained increasing attention owing to their special advantages including high integration,...

Transparent glass ceramics (GCs) consisting of an homogeneous glass phase and a well-dispersed crystal phase are considered as ideal optical gain materials potentially applied in optoelectronic devices due to the combination of facile processability of glass and the intense crystal field of nanocrystals. Here, a heat-induced nanocrystal-in-glass method is employed to integrate the active ions Tm 3+ into Bi 2 Te 4 O 11 nanocrystals with an intense crystal field to realize an enhanced microlaser output. This strategy endows the efficient tellurate GC microcavity laser operating at ≈2 µm. Compared with the laser properties of as-prepared glass microcavities, the pump threshold (260 µW) is as low as less than a quarter and the slope efficiency (0.0296%) is 5.5 times higher. Furthermore, by carefully engineering the heat treatment temperature and duration, the crystal size and distribution can be precisely controlled. Thus, the Rayleigh scattering loss that is detrimental to quality (Q) factor is effectively suppressed and the GC microcavities with high Q factors up to 10 5 are successfully obtained. This work provides useful insight on the development of optical functional materials and expands the practical applications of GC microcavities in various optoelectronic fields.