In recent years, when the graphene industry is booming, another new type of single-element two-dimensional atomic crystal material-black phosphorus has been discovered. Similar to graphene, black phosphorus has many excellent properties, so it is called a “dream material” comparable to graphene. Its nonlinear optical characteristics have been confirmed by many domestic and foreign companies and have been used in the generation of ultrafast laser pointer.
In the laser field, devices with saturable absorption characteristics are the key to the formation of ultrashort pulse lasers. The discovery of black phosphorous broadband saturable light absorption characteristics, and the wavelength range covering visible light to mid-infrared wavelengths, provides the possibility for the development of mid-infrared ultrafast optical devices.
Studies have shown that graphene is a semi-metal semiconductor material with no band gap, with ultra-high electron mobility and broadband light absorption characteristics. However, the band-gap-free energy band structure limits the application and development of graphene in the field of optoelectronics. The biggest feature of black phosphorus is that it has a direct band gap that changes with the number of layers, which just solves the problem that plagues graphene.
Low-cost diffraction-limited organic lasers from the XIII University of Paris, the French National Center for Scientific Research, Semileber Semiconductor Physics Laboratory, and the Saint-Etienne Advanced School of Mining, through the joint efforts of scientists, prepared an inkjet printing method. Kind of laser core. The thin-film organic external cavity vertical emitting green laser pointer capsule can be prepared completely at one time.
The laser capsule made by inkjet printing is composed of EMD6415 ink with a refractive index of 1.5 as the main optical substrate, and is formed by a combination of standard laser dyes. Near the capsule is a Fabry-Perot etalon based on inner-cavity polymers that allows the laser output to be continuously tuned from 570 nm to 670 nm.
Although the cost of organic lasers is relatively low, their ability to degrade quickly becomes one of the obstacles. Perhaps this obstacle is not so terrible, because since this kind of laser is so cheap, once it is degraded, it can be thrown away. Researchers estimate that the production cost of each laser capsule is only a few cents.