METHOD OF VARYING NECK DIAMETER OF OUTPUT LASER BEAM AT FIXED DISTANCE FROM LASER Russian patent published in 2013 - IPC G02B27/09 H01S3/10 

FIELD: physics.

SUBSTANCE: method of varying neck diameter of an output laser beam at a fixed distance from the laser is realised by a device having a laser which emits a beam with neck diameter 2h_p1 and a confocality parameter z_k1, a two-component optical system which forms, in the initial position of components, an output neck with diameter $$2h_{p20}^{\text{'}}$$ at a distance L₀ from the laser, each component of the optical system being capable of moving along an optical axis. Matched displacement of components is carried out along the optical axis according to the law s₂(s₁)=a·y(s₁)-Δ₀+s₁, where: s₁ and s₂ are displacements of the first and second components of the optical system; $$a=f_1^{\text{'}2}/z_{k1};$$ Δ₀ is the distance between the rear focus F₂ of the first component and the front focus F₂ of the second component in the initial position. Parameter y is determined by solving the cubic equation $$a^2\left(x^2+1\right)y^3+a\left[2ax-b\left(x^2+1\right)\right]y^2+\left[a\left(a-2bx\right)+f_2^{\text{'}2}\left(x^2+1\right)\right]y+x{f}_2^{\text{'}2}-ab=\mathrm{0,}$$ where $$x=\frac{z_{p10}-s_1}{z_{k1}};$$ $$b=z_{p20}^{\text{'}}+{\Delta }_0-s_1;$$ z_p10 is the position of the neck of the input beam relative the front focus F₁ of the first component in the initial position; $$z_{p20}^{\text{'}}$$ is the position of the output neck relative the rear focus $$F_2^{\text{'}}$$ of the second component in the initial position; $$f_1^{\text{'}}$$ and $$f_2^{\text{'}}$$ are the back focal distances of the components.

EFFECT: enabling formation of a laser beam with a variable neck diameter at a fixed distance from the laser.

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