Single crystal polarizing prism and method of manufacturing thereof

A method of manufacturing an anisotropic polarizing prism for polarization of a non-polarized light characterized by a wave vector, said prism being made of a single-crystal material, said prism having a first base plane, a second base plane which forms a first angle α with said first base plane, a third base plane located opposite to said second base plane and forming a second angle β with said first base plane, and a fourth base plane located opposite to said first base plane and forming a third angle γ with said second base plane, said prism providing reflection of a beam incident on said second base plane through said first base plane in two directions in the form of an e-beam and an o-beam having an angle δ of separation, said e-beam having an angle of reflection smaller than an angle of reflection of said o-beam and propagates in a direction of propagation towards said third base plane, said method comprising the steps of:

• selecting a material for said anisotropic polarizing prism from single-axis crystals, each of said single-axis crystals having an optical axis;
• determining, the orientation of said optical axis with respect to the normal to the plane of total internal reflection from said second plane;
• calculating dependence of said angle δ from an angle ν between said normal to said second base plane and said optical axis;
• finding a negative extreme in said dependence;
• finding a value of said angle ν within the range of ±10% of said angle ν for said negative extreme calculated in said step of calculating and found in said step of finding a negative extreme;
• forming said second base plane of said prism so that said normal to said second base plane forms said angle ν with said optical axis;
• forming said first base plane so that a normal to said first base plane be coplanar to a plane which contains said normal to said second base plane and said optical axis and so that said e-beam is refracted on said third base plane in a first point and exits said prism at a Brewster angle from said first point, while said o-beam is reflected from said third base plane with total internal reflection from a second point which is different from said first point and exits said prism through said fourth base plane;
• forming said third base to obtain said Brewster angle and said total internal reflection;
• and
• forming said fourth base plane so that said o-beam can exit said prism through said fourth base plane along the normal to said fourth plane.

A method of manufacturing an anisotropic polarizing prism for polarization of a non-polarized light characterized by a wave vector, said prism being made from biaxial crystals, said prism having a first base plane, a second base plane which forms a first angle α with said first base plane, a third base plane located opposite to said second base plane and forming a second angle β with said first base plane, and a fourth base plane located opposite to said first base plane and forming a third angle γ with said second base plane, said prism providing reflection of a beam incident on said second base plane through said first base plane in two directions in the form of an e-beam and an o-beam having an angle δ of separation, said e-beam having an angle of reflection smaller than an angle of reflection of said o-beam and propagates in a direction of propagation towards said third base plane, said method comprising the steps of:

• selecting a biaxial crystal for said anisotropic polarizing prism from biaxial crystals, said biaxial crystal having three main sectional planes of Fresnel indicatrix with axes of the optical indicatrix characterized by Nx=Nmin, Ny=Nmean, and Ny=Nmax, where Nx, Ny, and Nz are main values of refraction indices along axes X, Y, and Z, respectively, and where “min” designates “minimal”, “mean” designates an average, and “max” designates “maximal”;
• determining one of said three main section planes of propagation of the beams to form a selected plane and then determining the orientation of one of the axes of the optical indicatrix located in said selected plane;
• calculating dependence of said angle δ from an angle ν between said normal to said second base plane and said one of the axes of the optical indicatrix located in said selected plane;
• finding a negative extreme in said dependence;
• finding a value of said angle ν within the range of ±10% of said angle ν for said negative extreme calculated in said step of calculating and found in said step of finding a negative extreme;
• forming said second base plane of said prism so that said normal to said second base plane forms said angle ν with said one of the axes of the optical indicatrix located in said selected plane;
• forming said first base plane so that a normal to said first base plane be coplanar to a plane which contains said normal to said second base plane and said one of axes of the optical indicatrix located in said selected plane so that said e-beam is refracted on said third base plane in a first point and exits said prism at a Brewster angle from said first point, while said o-beam is reflected from said third base plane with total internal reflection from a second point which is different from said first point and exits said prism through said fourth base plane;
• forming said third base to obtain said Brewster angle and said total internal reflection;
• and
• forming said fourth base plane so that said o-beam can exit said prism through said fourth base plane along the normal to said fourth plane.