Patent ID: 6243219
Filing Date: 2001-06-05
Classification: A61B,A61F,G02B,G02F

Abstract:
A method of limiting the passage of laser light through a solid substantially transparent medium in response to said laser light having a selected wavelength impinging on said medium comprising the steps of:inserting into a path of a laser light beam said substantially transparent medium, said substantially transparent medium having incorporated therein a dopant of ions at least one transition metal, said medium being an inorganic crystal; said ions exhibiting ground state absorption over a first band of light wavelengths; said ions further exhibiting excited state absorption over a second band of light wavelengths, said first band of light wavelengths and second band of light wavelengths overlapping; said overlapping bands of said ground state absorption and said excited state absorption both including the wavelength of said laser light to be limited;said transparent material selected from a group consisting of YA10.sub.3 , Y.sub.3 AI.sub.5 O.sub.12 and Gd.sub.3 Ga.sub.5 O.sub.12, andsaid dopant comprises ions selected from the group consisting of Mn.sup.4+ ; Mn and Ca; Mn and Mg; Mn and Ca and Mg; and Mn.sup.4+ and Co;receiving sufficient intensity of said laser light beam onto said medium to cause excited state absorption of said laser light beam by exciting said ions from a ground state to an excited state and absorbing a portion of said laser light beam, andabsorbing a further portion of said light of said laser beam by said ions in said excited state to non-linearly absorb said laser light,thereby limiting the transmission of said laser light through said medium.