Document ID: chunk:federal_register_of_legislation:F2024L01024:front:0:p197
Version: federal_register_of_legislation:F2024L01024
Segment Type: other
Provision Reference: 
Character Range: 570044–572745

more than 100 Hz and an "accuracy" of 10 μrad or less (better);
6. A. 004. d. 3. Gimbals having all of the following:
a. A maximum slew exceeding 5°;
b. A bandwidth of 100 Hz or more;
c. Angular pointing errors of 200 µrad (microradians) or less; and
d. Having any of the following:
1. Exceeding 0.15 m but not exceeding 1 m in diameter or major axis length and capable of angular accelerations exceeding 2 rad (radians)/s2; or
2. Exceeding 1 m in diameter or major axis length and capable of angular accelerations exceeding 0.5 rad (radians)/s2;
6. A. 004. d. 4. Not used;
6. A. 004. e. 'Aspheric optical elements' having all of the following:
1. Largest dimension of the optical‑aperture greater than 400 mm;
2. Surface roughness less than 1 nm (rms) for sampling lengths equal to or greater than 1 mm; and
3. Coefficient of linear thermal expansion's absolute magnitude less than 3 x 10‑6/K at 25°C.
Technical Notes:
1. For the purposes of 6A004.e., an 'aspheric optical element' is any element used in an optical system whose imaging surface or surfaces are designed to depart from the shape of an ideal sphere.
2. For the purposes of 6A004.e.2., manufacturers are not required to measure the surface roughness unless the optical element was designed or manufactured with the intent to meet, or exceed, the specified parameter.
Note: 6A004.e. does not apply to 'aspheric optical elements' having any of the following:
a. Largest optical‑aperture dimension less than 1 m and focal length to aperture ratio equal to or greater than 4.5:1;
b. Largest optical‑aperture dimension equal to or greater than 1 m and focal length to aperture ratio equal to or greater than 7:1;
c. Designed as Fresnel, flyeye, stripe, prism or diffractive optical elements;
d. Fabricated from borosilicate glass having a coefficient of linear thermal expansion greater than 2.5 x 10‑6 /K at 25°C; or
e. An x‑ray optical element having inner mirror capabilities (e.g., tube‑type mirrors).
N.B.: For 'aspheric optical elements' specially designed for lithography equipment, see 3B001.
6. A. 004. f. Dynamic wavefront measuring equipment having all of the following:
1. 'Frame rates' equal to or more than 1 kHz; and
2.  A wavefront accuracy equal to or less (better) than λ/20 at the designed wavelength.
Technical Note:
For the purposes of 6A004.f., 'frame rate' is a frequency at which all "active pixels" in the "focal plane array" are integrated for recording images projected by the wavefront sensor optics.
6. A. 005. "Lasers", other than those specified by 0B001.g.5. or 0B001.h.6., components and optical equipment, as follows:
N.B.: SEE ALSO 6A205.
Note 1: Pulsed "lasers" include those that run in a continuous wave