Fabrication And Study Of Spherical Gradient-index Lenses And Its Optical Characteristics

Above all, this paper briefly introduces the development survey of the gradient-index matter and the spherical gradient-index lenses, as well as its theoretic and practical significances. Secondly, emphatically studies the optical characteristics, imaging characteristics and coupling characteristics. At last, the fabrication and testing of the gradient-index ball lenses is simply studied and the satisfactory results are attained.The achievements of theory research work on the gradient-index ball lens are listed as follows:1. According to the Principle of Fermat and the equation of ray, we get the solution of ray trace equation for the gradient-index ball lens whose refractive index is the distributing of square parabola rules like n(r) = n(0)(1-1/2Ar2). If wechose appropriate parameters, we can depict its trace that is elliptic.2. Using the ray-matrix way, we study the imaging characteristic of the spherically gradient-index lens, and come to the conclusion of expressions on its object and image and the focal length.3. We make researches on the coupling efficiency of the gradient-index ball lenses, which are used as couplers between the LED and the optical fiber, and the results show that we can attain a high efficiency when the gradient-index ball lenses are used as couplers.The experimental results of the fabrication and testing of the gradient-index ball lens are listed as follows:1. Using the way of fusion and the ion exchange technique, we develop the gradient-index ball lenses, which are made of glass containing thallium element. Through testing, we arrive at the conclusion that the refractive index of the ball lenses is square and their diameters range from 2.0-3.0 millimeter.2. In the course of the ion exchange, we find that the optimum temperature is between 510℃ and 530℃. In our experiments, we chose 518℃ as experiment temperature, and the result is satisfactory.3. The testing results are expectant, such as the distributing of index, focal length, effective numerical aperture, facular size and coupling efficiency.