Depth imaging is very important for many emerging technologies, such as artificial intelligence, driverless vehicles and facial recognition. However, all these applications demand compact and low-power systems that are beyond the capabilities of most state-of-art depth cameras. Recently, metasurface-based depth imaging that exploits point spread function (PSF) engineering has been demonstrated to be miniaturized and single shot without requiring active illumination or multiple viewpoint exposures. A pair of spatially adjacent metalenses with an extended depth-of-field (EDOF) PSF and a depth-sensitive double-helix PSF (DH-PSF) were used, using the former metalens to reconstruct clear images of each depth and the latter to accurately estimate depth. However, due to these two metalenses being non-coaxial, parallax in capturing scenes is inevitable, which would limit the depth precision and field of view. In this work, a bifunctional reconfigurable metalens for 3D depth imaging was proposed by dynamically switching between EDOF-PSF and DH-PSF. Specifically, a polarization-independent metalens working at 1550 nm with a compact 1 mm2 aperture was realized, which can generate a focused accelerating beam and a focused rotating beam at the phase transition of crystalline and amorphous Ge2Sb2Te5 (GST), respectively. Combined with the deconvolution algorithm, we demonstrated the good capabilities of scene reconstruction and depth imaging using a theoretical simulation and achieved a depth measurement error of only 3.42%.
With the ever-increasing laser power and repetition rate, thermal control of laser media is becoming increasingly important. Except for widely used air cooling or a bonded heat sink, water cooling of a laser medium is more effective in removing waste heat. However, how to protect deliquescent laser media from water erosion is a challenging issue. Here, novel waterproof coatings were proposed to shield Nd:Glass from water erosion. After clarifying the dependence of the waterproof property of single layers on their microstructures and pore characteristics, nanocomposites that dope SiO2 in HfO2 were synthesized using an ion-assisted co-evaporation process to solve the issue of a lack of a high-index material that simultaneously has a dense amorphous microstructure and wide bandgap. Hf0.7Si0.3O2/SiO2 multifunctional coatings were finally shown to possess an excellent waterproof property, high laser-induced damage threshold (LIDT) and good spectral performance, which can be used as the enabling components for thermal control in high-power laser cavities.
Objective To explore the inhibition of the proliferation of vulvar squamous cell carcinoma (VSCC) by astragaloside IV. Methods MTT examined the cell proliferation of VSCC. Flow cytometry analyzed cell cycle and apoptosis. Western blot assay detected the expression of some relevant proteins. Results AS‐IV reduced the proliferation of SW962 cells in a concentration‐ and time‐dependent manner, induced cell‐cycle arresting in G0/G1 phase, as demonstrated by the up‐regulation of P53 and P21 expression, and the down‐regulation of cyclin D1 expression. AS‐IV enhanced the expression of Bax and cleaved‐caspase 3, and suppressed Bcl‐2 and Bcl‐xl expression, which resulted in apoptosis increased. Furthermore, the expression of Beclin‐1 and LC3‐B was upregulated and that of P62 was downregulated, which suggested that AS‐IV could increase the incidence of autophagy in SW962 cells. After inhibiting autophagy by 3‐methyladenine (3‐MA), cell apoptosis decreased upon AS‐IV treatment. Similarly, TGF‐β1 stimulated SW962 cells, cell proliferation enhanced, and the expression of TGF‐βRII and Smad4 was decreased. Furthermore, the expression of proteins that promote apoptosis and autophagy decreased. After AS‐IV treatment, the expression levels of the above proteins exhibited the opposite effect. Conclusion AS‐IV inhibits cell proliferation and induces apoptosis and autophagy through the TGF‐β/Smad signaling pathway in VSCC.
Hybrid organic-inorganic perovskite shows a great potential in the field of photoelectrics. Embedding methyl ammonium lead bromide (MAPbBr3) in a mesoporous silica (mSiO2) layer is an effective method for maintaining optical performance of MAPbBr3 at room temperature. In this work, we synthesized MAPbBr3 quantum dots, embedding them in the mSiO2 layer. The nonlinear optical responses of this composite thin film have been investigated by using the Z-scan technique at a wavelength of 800 nm. The results show plural nonlinear responses in different intensities, corresponding to one- and two-photon processing. Our results support that composites possess saturation intensity of ~27.29 GW/cm2 and varying nonlinear coefficients. The composite thin films show high stability under ultrafast laser irradiating. By employing the composite as a saturable absorber, a passively Q-switching laser has been achieved on a Nd:YVO4 all-solid-state laser platform to generate a laser at ~1 μm.
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