The Research Of White Light Up Conversion Laser Device Based On Rare Earth Doped CaF2 Glass

As a new type of solid lighting technology,white lasers are of great significance in our lives and work.Nowadays,white light source based on single material is one of the hot spots of international research.The luminescence spectrum of rare earth covers the UV-VIS-IR spectrum.A white light upconverting luminescent material can be obtained by doping a different rare earth in the host material.White upconverting laser has a unique set of properties,such as high monochromaticity,coherence,and directionality.However,due to t he lack of a suitable laser cavity,there have been few reports in recent years.The whispering gallery mode?WGM?microtoroidal resonator can limit the energy of light to a small volume for a long time without loss.WGM has a very high quality factor.The refore,in this paper,the white light upconverting luminescent material is combined with the microtoroidal resonator of WGM to obtain a white laser of WGM.In this paper,CaF₂ is used as the matrix material of rare earth doped glass.he material has high thermal stability,low phonon energy,good mechanical properties and high refractive index,which can effectively reduce the non radiation composite loss and concentration quenching effect,so the up conversion efficiency is high.Then,the effect mechanism of the doping ratio of rare earth ions on the white light output in the Yb³⁺-Er³⁺-Tm³⁺ co-doped system was studied.Yb3+ is used as a sensitizer ion to absorb the energy of the pump light and transfer it to the activator ion.Er3+ and Tm3+ act as activator ions and obtain red?658 nm?,green?545 nm?,and blue?475 nm?emissions,respectively.By adjusting the doping ratio of rare earth ions,the light intensity ratio of red light,green light and blue light is further adjusted,and finally stable white light emission is obtained.In this paper,a combination of photolithography and inductively coupled plasma etching is used to obtain a disk microcavity with a suspended structure.The disk microcavity is prepared into a high quality factor microtoroidal resonator by a CO₂ laser reflow process.Coupling uses self-made tapered fiber.The quality factor of the microtoroidal resonator is as high as 7.8×106.In this paper,a more flexible and simple sol-gel method is used to prepare rare earth ions doped films.The sol is spin-coated on a disk microcavity of a suspended structure prepared by a micro-nano process.We can obtain microtoroidal resonator containing rare earth ions doping by CO₂ laser reflow process.Under the 980 nm pulsed laser pumping,the microtoroidal resonator different sizes saw the emission of WGM mode laser at 654 nm,540 nm and 450 nm,and the threshold decreased with increasing size.Different sizes of microtoroidal resonator laser patterns were introduced into CIE1931,and the coordinates were basically close to standard white light?0.33,0.33?,and white light laser emission with WGM mode can be obtained.