What is the use of the absolute reference?
In direct laser writing system, the absolute reference is used for the control of the focal system (z) and of the motors (x and y).
How is the absolute reference implemented in Kloe’s direct laser writing equipment?
In our Dilase direct laser writing systems, we use optical encoders, which are made into zerodur substrate (very few sensitive with temperature variations), and on which a Bragg grating is engraved.
What is the point of using a Bragg grating?
The grating pitch will define interferences. When calibrating the machine, before the 1st use, 0 point, aka the absolute reference, will be physically determined using the grating pitch.
What is the interest of absolute reference?
As the 0 point, the absolute reference, exists physically, the 0 point of the machine does not move, including the 0 point of the focal.
The absolute reference therefore makes it possible to obtain a true mode of vectorial writing: during writing, the optical rule is permanently interrogated, for all the motors (x, y and z). The control of the motors is therefore done in dynamic mode.