Study On Multi-Wavelength All-Solid-State Laser For Retinal Photocoagulation

Laser has been an irreplaceable implement for eye surgery as medical technologyevolving, especially in the treatment of retinal diseases. Accurate and efficient red, yellow,green, multi-wavelength lasers are very promising medical laser equipment in recent years.The development of all-solid-state small-scale cw multi-wavelength laser for laser eyetreatment of has become a hot spot.First, the optical resonator stability condition contains has been calculated; the impactof the optical resonator, which causes by various kinds of thermally induced distortion tothe active medium, has been analysed; the gain distribution of the active medium in normaloperation has been studyed, and the formulas of the spot diameter, beam divergence angle,beam quality of the product, and other parameters have been obtained. It providestheoretical guidances to design all-solid-state laser resonator and to improve the quality ofthe laser output.Secondly, the reflectivity formula of the reflective films, which ensure the oscillationfor a specific wavelength laser in the optical resonator, has been derived; the angle-matching,the effective non-linear coefficient and other important parameters in different phase-matchinghave both been calculated. It provides the theoretical basis for output more lasers ondifferent wavelength.Since then, three kinds of infrared wavelength (1064nm,1122nm,1320nm)solid-state lasers have been design and manufacture, obtained22.9W,10.1W,13.9W outputpower respectively; and three kinds of visible light wavelength (532nm,561nm,660nm)solid-state lasers, which is frequency doubled by the KTP crystal, obtained9.6W,4.1W,6.3W of output power respectively. Six kinds of wavelength of the laser all have beenoutput by fiber-coupled and the optical coupling efficiencies are all more than80%. Use aY-shaped fiber-coupled the lasers of the two frequencies, to facilitate the multi-wavelengthlaser access to the terminal equipment for retinal photocoagulation, and to make thetreatment convenient. The three colors laser (red, yellow and green) according therequieminets to work alone or simultaneously. Red, yellow and green laser has ownadvantage and insufficient in eye treatment. This system will allow them three complementeach other, can be applied to a wider range of surgery, even better treatment. Finally, the applications of the multi-wavelength laser have been classified inaccordance with the standards of different symptoms, according to the theory of theexisting role of laser and biological tissue. And based on the actual fundus clinical disease,describes the selection and combination of the wavelength, spot diameter, length ofexposure and the power.It is very effective that the multi-wavelength laser is used for retinal treatmentinstrument, whether the three kinds of laser work alone or simultaneously. At present, thereare few studies on the use of the laser, especially red and yellow, for retinal diseasetreatment, and the use of multi-wavelength laser for retinal disease treatment has not yetappeared interiorly. In abroad, only the LUMENS (a company in United States) haverelated products for sell. The devices in this article has far-reaching significance to breakthe monopoly of foreign companies in China market, as well as the benefit of the majorityof patients.