Manganese dioxide as wide adaptive ultrafast photonic device for pulsed laser generation

Research on novel ultrafast photonic devices with wide adaptability has become important scientific technical means to realize both scheme innovation and performance breakthrough in fiber laser generation.As types of transition metal oxide,manganese dioxide(MnO_(2))materials exhibit remarkable properties including high photothermal stability,strong oxidation resistance,and excellent optical properties,making them promising candidate for utilization as modulation devices in nonlinear optics and ultrafast optics fields.We investigate the impact of MnO_(2)-based saturable absorber(SA)on the pulse characteristics.The experiment reveals that MnO_(2)-based SA supports effectively pulsed laser generation in wide pump power range and large dispersion parameter space with signal-to-noise ratio more than 85 dB.As far as we know,the pump power response range is outstanding among the most of the reported pulsed lasers,which is attributed to the large modulation depth of MnO_(2) SA.We also investigate the impact of dispersion on the characteristics of laser output,which is not involved in other similar works.This research indicates that MnO_(2) as a photonic device has vast potential in advanced ultrafast optics.

Transparent Thermally Tunable Microwave Absorber Prototype Based on Patterned VO2 Film

Transparent microwave absorbers that exhibit high optical transmittance and microwave absorption capability are ideal,although having a fixed absorption performance limits their applicability.Here,a simple,transparent,and thermally tunable microwave absorber is proposed,based on a patterned vanadium dioxide(VO_(2))film.Numerical calculations and experiments demonstrate that the proposed VO_(2)absorber has a high optical transmittance of 84.9%at 620 nm;its reflection loss at 15.06 GHz can be thermally tuned from–4.257 to–60.179 dB,and near-unity absorption is achieved at 523.750 K.Adjusting only the patterned VO_(2)film duty cycle can change the temperature of near-unity absorption.Our VO_(2)absorber has a simple composition,a high optical transmittance,a thermally tunable microwave absorption performance,a large modulation depth,and an adjustable temperature tuning range,making it promising for application in tunable sensors,thermal emitters,modulators,thermal imaging,bolometers,and photovoltaic devices.