Green technology advancement, energy input share and carbon emission trend studies.

In order to study the theoretical mechanism of the impact of green technology progress on carbon emissions, this article constructs a theoretical mechanism of the impact of green technology progress on carbon emission growth. Explore the conditions for achieving carbon peak and carbon reduction. Based on the Cobb Douglas production function, construct a three sector model that includes capital, labor, and energy.

2 µm band four-wavelength-switchable narrow linewidth fiber laser enabled by fs-laser direct-written polarization-dependent parallel fiber Bragg gratings.

We propose and experimentally demonstrate a four-wavelength-switchable single-longitudinal-mode (SLM) narrow linewidth thulium-holmium co-doped fiber laser (THDFL) using two polarization-dependent parallel fiber Bragg gratings (PD-PFBGs). The PD-PFBGs, fabricated using femtosecond (fs) laser direct-writing technology in a standard single-mode fiber (SMF) via a point-by-point method, are used as a four-channel reflection filter. Two FBGs are inscribed in parallel in the fiber core along the axial direction and are uniquely positioned symmetrically on either side of the centerline.