Abstract:The different upconversion dynamic processes in Tm,Ho:GdVO4 crystal pumped by 100 fs pulse laser and continue-wave diode laser at 800 nm are analyzed. A phononhelped absorption theory is used to explain the different upconversion processes in Tm,Ho:YLF and Tm,Ho:GdVO4. In addition, the lifetime 16 µs of Ho:5 S2 level in GdVO4 is firstly measured.Spectrum intensity, a.u.
To simultaneously achieve a high optical-transparency and Wi-Fi bandpass filtering characteristics for optical windows, a novel meshcoated frequency selective surface (FSS) is designed and fabricated using an ultraviolet lithography technique. Simulation and experimental results show that the resonant centre frequency of the proposed mesh-coated FSS is about 5.3 GHz with a transmittance loss of −2 dB, while its optical transmittance is above 87.5% in the infrared (IR) waveband ranging from 1.35 to 3.3 μm. Moreover, such a FSS has the merits of ameliorable electromagnetic shielding effectiveness and improvable optical transmittance by optimising the thickness of the mesh layer. Both the design procedure and experimental measuring results are presented and discussed.Introduction: A frequency selective surface (FSS) is an array of periodic apertures perforated on a conducting sheet or metallic patches in a substrate which exhibits bandpass or band-stop responses. The FSS has been widely studied because of its various applications from microwave, radar to infrared (IR) and THz [1-5]. However, a traditional bandpass FSS with a thick metal plate cannot satisfy optical transparency and wireless communication applications, such as optical windows for enhanced Wi-Fi bandpass in important private buildings. An opticaltransparent FSS is proposed in [6], which is etched on thin indium tin oxide (ITO) films. This kind of FSS is used for low-emissivity (energy saving) windows since an ITO layer reflects a significant portion of long and short IR wave energy [7]. The restrictive relation between conductivity and transparency of ITO is a fatal contradiction [8]. Besides, the ITO optical-transparent FSS cannot be used for high IR transmission. Enlightened by this idea, an optical-transparent meshcoated FSS is designed and fabricated in this Letter. Its resonant frequency is about 5.3 GHz with a transmittance loss of −2 dB, while the optical transmittance is above 87.5% in the IR waveband ranging from 1.35 to 3.3 μm.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.