Over a decade, considerable development has been achieved in microsphere microscopy; the popularity of this method is attributable to its compatibility with biomedical applications. Although microscopy has been used extensively, insufficient analyses and simulation approaches capable of explaining the experimental observations have hampered its theoretical development. In this paper, a three-stage full-wave simulation architecture has been presented for the in-depth analysis of the imaging properties of microspheres. This simulation architecture consists of forward and backward propagation mechanisms, following the concept of geometric optics and strictly complying to wave optics at each stage. Three numerical simulation methods, including FDTD, NTFF, and ASPW, are integrated into this simulation architecture to encompass near-field and far-field behaviors and relieve the computational burden. We validated this architecture by comparing our simulation results with the experimental data provided in literature. The results confirmed that the proposed architecture exhibits high consistency both qualitatively and quantitatively. By using this architecture, we demonstrated the near-field effect of the samples on the resolution and provided evidence to explain the conflicts in literature. Moreover, the flexibility and versatility of the proposed architecture in modeling allow adaptation to various scenarios in microsphere microscopy. The results of this study, as an imaging analysis and system design platform, may facilitate the development of microsphere microscopy for biomedical imaging, wafer inspection, and other potential applications.Microfiber gratings with diameters in the subwavelength scale have recently attracted much attention for developments of sensitive sensors; however, a specific structure is usually chosen for sensing one parameter according to the optical response. In this work, a superstructure microfiber grating combined with microfiber Bragg grating and long-period microfiber grating is reported for the first time. The proposed superstructure is formed by ultraviolet laser inscription and femtosecond laser scratching techniques, which simultaneously endows the unique properties of the two individual gratings. The reflection and transmission spectral characteristics differing to conventional counterparts are demonstrated. The responsivities of the two gratings to temperature, strain and refractive index are investigated, providing a possibility for simultaneous multi-parameter sensing.We demonstrate a novel ErLuSGG active gain medium emitting laser wavelength at 2795 nm for the first time. The ErLuSGG crystal is grown successfully by the Czochralski method with high crystalline and optical quality. The spectra properties, including absorption and fluorescence emission cross-section are presented in contrast with similar Er-doped garnet crystals. The fluorescence lifetimes of the upper (4I11/2) and lower (4I13/2) laser levels are 1.75 and 4.64 ms, respectively. Under 973 nm laser diode pumping, a maximum output power of 789 mW in continuous-wave mode, corresponding to optical-to-optical efficiency of 20.2% and slope efficiency of 24.4%, is achieved with high laser beam quality. FDI-6 research buy The results show that the ErLuSGG is a promising MIR laser material operated at 2.8 µm.Recently, the negative absorption in graphene-based metamaterials became a very attractive direction of THz electronic devices. Here we propose a graphene-dielectric hybrid meta-structure to realize photo-induced enhanced negative absorption in the THz regime, which results from strong graphene-light interaction. The negative absorption is derived from the degradation of the conductivity of graphene under optical pump. Meanwhile, the graphene-dielectric hybrid meta-structure introduces dispersion relation and resonance mode, which can couple with the incident wave to construct a strong resonance. In this case, both the dispersion of the propagating waves and resonance are contributed to the graphene-light interaction and enhance the negative absorption, in which the resonance coupling determines the distribution of negative absorption, and the maximum is dominated by dispersion. More importantly, compared with the previous work, the negative absorption is increased by nearly 100 times by adopting this meta-structure.Time-resolved optical spectroscopy (TR-OS) has emerged as a fundamental spectroscopic tool for probing complex materials, to both investigate ground-state-related properties and trigger phase transitions among different states with peculiar electronic and lattice structures. We describe a versatile approach to perform polarization-resolved TR-OS measurements, by combining broadband detection with the capability to simultaneously probe two orthogonal polarization states. This method allows us to probe, with femtoseconds resolution, the frequency-resolved reflectivity or transmittivity variations along two mutually orthogonal directions, matching the principal axis of the crystal structure of the material under scrutiny. We report on the results obtained by acquiring the polarization-dependent transient reflectivity of two polytypes of the MoTe2 compound, with 2H and 1T' crystal structures. We reveal marked anisotropies in the time-resolved reflectivity signal of 1T'-MoTe2, which are connected to the crystal structure of the compound. Polarization- and time- resolved spectroscopic measurements can thus provide information about the nature and dynamics of both the electronic and crystal lattice subsystems, advancing the comprehension of their inter-dependence, in particular in the case of photoinduced phase transitions; in addition, they provide a broadband measurement of transient polarization rotations.We demonstrate a lateral, planar fiber-to-waveguide coupling strategy for photonic integrated circuits with diffraction grating couplers using angle-polished silica waveguide blocks fabricated with well-established planar lightwave circuit technologies. Compared to the conventional lateral coupling scheme with angle-polished fibers, the demonstrated scheme can significantly decrease the diverging distance between the reflective angle-polished facet and the grating couplers, and thereby maintains the overall coupling efficiency and alignment tolerances of the vertical coupling approach. The proposed method shows a small penalty in coupling efficiency ( less then 0.1 dB), and in-plane (out-of-plane) alignment tolerance for 1 dB excess loss is approximately 5 µm (9 µm).