Wavelength-Dependent Transient Characteristics Caused by Gain Saturation in Highly Nonlinear Fiber-Based Raman Amplifiers

We have investigated the transient characteristics of discrete Raman Amplifiers and found that the response time caused by gain saturation is dependent upon the wavelength, which corresponds to the effective length of the pump light.

EFFECTS OF SPECTRAL DEPENDENCE IN PASS-THROUGH PHOTON-BASED BIOMEDICAL TRANSILLUMINATION

We have proposed an interferometric setup for biomedical analysis in transillumination modality.Wavelength dependence of optical properties must be considered for selecting source and sample.An expansion of the sample optical properties,around the central wavelength of emission,serves to account for spectral effects.Expected spectral values depend on the central moments of the source,and specific constants associated to the optical properties of the sample.By matching wavelength characteristics of source and sample,a first-order approximation is applicable.In such case,the expected values are exactly the optical properties evaluated at the central wavelength.Furthermore,in the first-order approximation,the transillumination interferometer yields the integrated attenuation of the sample at the central wavelength of emission.We verify the latter assertion by performing a wavelength-dependent Monte Carlo analysis to calculate the response of the transillumination interferometer.Recovered attenuation coefficients,for imaging and characterization scenarios,are in agreement with the value computed at the central wavelength of the source.

Au(Ⅰ)-BSA nanocomposites with assembling-induced excitation-dependent multicolor emission for dynamic cell imaging

Excitation wavelength dependent(Ex-De) luminescent materials have attracted intense attention due to their great potential in multicolor bioimaging,dynamic anti-counterfeiting,and light emitting devices.However,it remains a formidable challenge to construct an Ex-De luminescent biomaterial with green starting materials,excellent biocompatibility,good water solubility,and multiple color emission for dynamic cell imaging.In this work,nanocomposites based on the facile self-assembly strategy of bovine serum albumin(BSA) and Au(Ⅰ)-complex are rationally designed and synthesized to simultaneously present Ex-De fluorescence(429–516 nm) and decent phosphorescence(~615 nm) in a dilute aqueous solution.Combinatory analyses of spectroscopic and microscopic results reveal that the luminescent mechanism of Au(Ⅰ)-BSA nanocomposites is cluster-induced Ex-De fluorescence and metal-to-ligand charge transition(MLCT) based phosphorescence.Importantly,based on the excellent biocompatibility,water-solubility and color-tunable emission over the entire visible region(360–800 nm),the Au(Ⅰ)-BSA nanocomposites are successfully used for cell imaging with multiple and switchable colors on demand.What is more,the solid tablets of Au(Ⅰ)-BSA nanoparticles showed pressure-responsive luminescence and decent room temperature phosphorescence.This work provides an assembling-induced emission strategy for the design of water-soluble,non-cytotoxic,and color-tunable luminescent biomaterials based on the composite of protein and Au nanoparticles.

Non-ultrawide bandgap CsPbBr_(3) nanosheet for sensitive deep ultraviolet photodetection

In this study,we report the fabrication of a sensitive deep ultraviolet(DUV)photodetector by using CsPbBr_(3) nanosheets synthesized through confined-space growth at room temperature.The peak pho-toresponse of the device upon illumination blueshifts with decreasing thickness and a 68 nm CsPbBr_(3) nanosheet based device displays a peak response to 265 nm illumination,showing responsivity and spe-cific detectivity of 85 mA/W and 4.05×1011 Jones at 3 V bias,respectively.Theoretical simulation re-veals that the blueshift is associated with the wavelength-dependent absorption coefficient of CsPbBr_(3) nanosheet:incident light with shorter wavelengths can be absorbed on the superficial surface,while long-wavelength light has a larger penetration depth,leading to dominant DUV absorption in thinner CsPbBr_(3) nanosheet.This work will shed light on the facile and cost-effective fabrication of DUV photode-tectors from non-ultrawide bandgap(UWBG)all-inorganic perovskite materials.

Indoor multisource channel characteristic for visible light communication

In this paper, we present a wavelength depended ray-tracing algorithm to model the indoor multisource channel impulse response for visible light communication （VLC）. We compare the multipath loss difference between multisource and unisource channel. We also analyze the root mean square （RMS） delay spread and average time delay of three typical wavelengths as VLC holds a wide spectrum from 380 nm to 780 nm, the spectral reflectance of walls is wavelength-dependent. And the result shows that the blue light emitting diode （LED） owns a larger communication bandwidth than other wavelengths in the room with plastic walls. Also, the path loss of three different wavelengths is compared.