摘要(英) |
This study has two sections. The first section is to verify that the Wavefront sensor being used is thermally calibrated for this work. Athermalized Wavefront sensor will compensate for the Micro Lens Array (MLA) expansion, lateral shift, Complementary Metal Oxide Semiconductor (CMOS) shift, and Thermal expansion of materials and minimize the aberration under thermal stress conditions. One way is to prove that the Displacement difference of the WFS image position is scaled down effectively after Thermal compensation.
The second part is to measure the amount of focal shift in the system per degree rise in temperature both experimental as well as theoretical. A heterodyne interferometer is used to measure the displacements in Nanometer precision even though the Linear stage is equipped with Grating encoders Since attached to the stage will experience Thermal expansion. The reason for using an Interferometer is it is independent of the system. The stage is heated to the required temperature condition using an air blower and the displacement caused by the thermal expansion of the stage is recorded in the μmD2 interface which is the stage Thermal shift. Meanwhile, the focal shift in the optics is calculated using Lens maker formula and the calculated result is verified using an Athermalized Wavefront sensor by capturing the Image position Z under Thermal conditions repeatedly. In summary, athermalized wavefront sensors provide robust, reliable, and precise performance across varying thermal conditions, making them indispensable in critical optical applications where environmental stability cannot be guaranteed.
Keywords: Heterodyne Interferometer, Shack Hartmann Wavefront sensor, Focal Shift, Thermal Calibration. |
參考文獻 |
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