Abstract A Faraday rotator for rotating the plane of polarization of visible or invisible optical radiation for use in optical devices such as an optical filter, isolator or switch is disclosed which comprises a non-magnetic garnet substrate, preferably Gd 3 Ga 5 O 12 , a ferrimagnetic garnet film, preferably of Y 3 Fe 5 O 12 , epitaxially grown on the substrate, and magnet means for inducing a magnetic field in the film for rotating the plane of polarization of a light-beam passing therethrough. The lattice constants as and a f of the substrate and film materials, respectively, are matched as closely as possible, with the difference a s - a f being preferably equal to or smaller than 0,001 A. This may be obtained by choosing materials where part of Gd is replaced by Dy in the substrate or part of Y is replaced by Gd or Tb in the film. The substrate is preferably a monocrystal slice cut with its normal inclined at an angle between 0° and 15° from a <110> axis or <211> axis.
A Faraday rotator comprising : a non-magnetic garnet substrate; a ferrimagnetic garnet film epitaxially grown on the substrate; and a magnet for inducing a magnetic field in said film for rotating the plane of polarization of a light-beam applied to said film within said film, said substrate and said film being made of a material selected so that the absolute value of the difference Δa = as - a f between the lattice constant a s of said substrate and the lattice constant a f of said film is equal to or smaller than 0. 001 A (angstrom).
Claim 2
Dependent Claim
98 words
A Faraday rotator comprising : a non-magnetic garnet substrate; a ferrimagnetic garnet film epitaxially grown on the substrate; and a magnet for inducing a magnetic field in said film for rotating the plane of polarization of a light-beam applied to said film within said film, said substrate and said film being made of a material selected so that the absolute value of the difference Δa = as - a f between the lattice constant a s of said substrate and the lattice constant a f of said film is equal to or smaller than 0. 001 A (angstrom).
Claim 3
Dependent Claim
42 words
A Faraday rotator as claimed in Claim 1 wherein said substrate consists of Gd 3 Ga 5 O 12 and said film consists of Gd x Y 3-x Fe 5 O 12 , where x ranges from 0. 18 to 0. 24.
Claim 4
Dependent Claim
41 words
A Faraday rotator as claimed in Claim 1 wherein said substrate comprises Gd 3 Ga 5 0 12 and said film consists of Tb x Y 3 -x Fe 5 O 12 where x ranges from 0. 18 to 0. 24.
Claim 5
Dependent Claim
41 words
A Faraday rotator as claimed in Claim 1 wherein said substrate comprises Dy x Gd 3-x Ga 5 0 12 and said film consists of Y 3 Fe 5 O 12 , where x ranges from 0. 32 to 0. 37.
Claim 6
Dependent Claim
62 words
A Faraday rotator as claimed in Claim 1 wherein said substrate 1 is sliced out from a single crystal boule having a predetermined growth axis in such a way that said substrate has its normal inclined from a <110> axis toward a predetermined axis by an angle of α ° greater than 0 degree but equal to or smaller than 15 degrees.
Claim 7
Dependent Claim
59 words
A Faraday rotator as claimed in Claim 1 wherein said substrate is sliced out from a single crystal boule having a predetermined growth axis in such a way that said substrate has its normal inclined from a <211> axis toward a predetermined axis by an angle of α° greater than 0 degree but equal to.or samaller than 15 degrees.
Claim 8
Dependent Claim
34 words
A Faraday rotator as claimed in Claim 1 wherein said substrate has growth striation, and the light-beam is given to said film vertically to said growth striation from one end surface of said film.
Claim 9
Dependent Claim
61 words
A Faraday rotator as claimed in Claim 1 wherein said substrate is sliced out from a non-magnetic garnet single crystal having a <111> growth axis, said substrate having its normal inclined from a< 110> axis toward a <211> axis within a {110} plane by an angle of α ° greater than 0 degree but equal to or smaller than 15 degrees.
Claim 10
Dependent Claim
61 words
A Faraday rotator as claimed in Claim 1 wherein said substrate is sliced out from a non-magnetic garnet single crystal having a <111> growth axis, said substrate having its normal inclined from a <211> axis toward a <110> axis within a {211} plane by an angle of α ° greater than 0 degree but equal to or smaller than 15 degrees.
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