ISO/TS 22247:2022 光学およびフォトニクス—レーザーレンズの有効開口数—定義および検証手順 | ページ 6

3.1

beam diameter

d_u (z)

<encircled power (energy)> diameter of a circular aperture in a plane perpendicular to the beam axis that contains u % of the total beam power (energy)

Note 1 to entry: For clarity, the term “beam diameter” is always used in combination with the symbol and its appropriate subscript: d_uord_σ .

[SOURCE:ISO 11145:2018, 3.3.1]

3.2

beam diameter

d_σ (z)

Note 1 to entry: For clarity, the term “beam diameter” is always used in combination with the symbol and its appropriate subscript: d_uord_σ.

[SOURCE:ISO 11145:2018, 3.3.2]

3.3

beam widths

d_x,u (z), d_y,u (z)

<slit transmitted power (energy)> width of the smallest slit aligned with the xory transverse axes of the power (energy) density distribution function, transmitting u % of the total beam power (energy) along xory

Note 1 to entry: For circular Gaussian beams, d_x,95,4 and d_y,95,4 both equal d_86,5.

Note 2 to entry: For clarity, the term “beam width” is always used in combination with the symbol and its appropriate subscripts: d_σx , d_σyord_x,u , d_y,u .

[SOURCE:ISO 11145:2018, 3.5.1]

3.4

beam widths

d_σx (z), d_σy (z)

Note 1 to entry: For clarity, the term “beam width” is always used in combination with the symbol and its appropriate subscripts: d_σx , d_σyord_x,u, d_y,u .

[SOURCE:ISO 11145:2018, 3.5.2]

3.5

beam waist

portion of a beam where the beam diameter or beam width has a local minimum

[SOURCE:ISO 11145:2018, 3.7.1]

3.6

beam waist diameter

d_0,u

<encircled power (energy)> diameter d_u of the beam at the location of the beam waist

[SOURCE:ISO 11145:2018, 3.7.4, modified — Note 1 to entry was deleted.]

3.7

beam waist width

d_x0,u , d_y0,u

<slit transmitted power (energy)> beam widths d_x,u and d_y,u at the locations of the beam waists in the x and y directions, respectively

[SOURCE:ISO 11145:2018, 3.7.8, modified — Note 1 to entry was deleted.]

3.8

beam waist location

z_0x , z_0y , z₀

location where the beam widths or the beam diameters reach their minimum values along the beam axis

[SOURCE:ISO 11145:2018, 3.7.2, modified — Note 1 to entry was deleted.]

3.9

astigmatic beam waist separation

Δz_a

axial distance between the beam waist locations in the orthogonal principal planes of a beam possessing simple astigmatism

[SOURCE:ISO 11145:2018, 3.7.3, modified — Note 1 to entry was deleted.]

3.10

divergence angle

Θ_u , Θ_x,u , Θ_y,u

<encircled, slit transmitted power (energy)> full angle formed by the asymptotic cone of the envelope formed by the increasing beam diameter (width)

[SOURCE:ISO 11145:2018, 3.8.1, modified — Notes 1 to 4 to entry and the example were deleted.]

3.11

divergence angle

Θ_σ , Θ_σx , Θ_σy

<second moment of power (energy) density distribution function> full angle formed by the asymptotic cone of the envelope formed by the increasing beam diameter (width)

[SOURCE:ISO 11145:2018, 3.8.2, modified — Notes 1 to 3 to entry were deleted.]

3.12

Rayleigh length

z_R, z_Rx, z_Ry

distance from the beam waist in the direction of propagation for which the diameter and beam width are equal to times their respective values at the beam waist

[SOURCE:ISO 11145:2018, 3.9.1, modified — Notes 1 and 2 to entry were deleted.]

3.13

beam propagation ratio

M²

measure of how close the beam parameter product is to the diffraction limit of a perfect Gaussian beam

Note 1 to entry: In contrast to ISO 11145:2018, 3.10.2, in this document the beam propagation ratio is not defined by the second order moments based definitions of beam diameter, beam width, and divergence angles, but instead by the power content based counterparts given in3.2, 3.4, and 3.11 of this document and ISO 11145:2018, 3.7.5 and 3.7.9.

3.14

residual divergence angle

angle of divergence Θ_u , Θ_xu , Θ_yu , Θ_σ , Θ_σx , Θ_σy of a divergent laser beam after collimation by a laser lens

3.15

effective numerical aperture

na_eff

sine of half of the maximum divergence angle, which a nearly diffraction limited beam can have before it is truncated by the finite geometry of the lens or its beam propagation ratio along the collimating direction of the lenses is increased by more than 0,5 due to aberrations

Note 1 to entry: The effective numerical aperture is always less or equal to the geometrical aperture of the lens.