Beyond the Surface: How ITF Enhances Accuracy in Optical Metrology

Modern optical systems require precise measurement of both vertical and lateral resolution to detect fine surface defects. The Instrument Transfer Function (ITF) is a key metric for evaluating measurement fidelity across spatial frequencies. A high ITF ensures accurate profiling of optics, critical for applications like space telescopes and high-power lasers.
July 2, 2025

As optical systems for space telescopes, defense, and satellite communications evolve, they demand increasingly precise manufacturing and measurement standards. A key challenge lies in accurately assessing both vertical and lateral resolution in optical components, as traditional metrology tools often sacrifice one for the other. This trade-off can obscure critical surface defects, leading to underperforming systems.

The Instrument Transfer Function (ITF) has emerged as a vital metric for evaluating the fidelity of optical measurements across varying spatial frequencies. ITF quantifies how well an interferometer captures the true surface profile of an optic, especially as feature sizes shrink. A high ITF ensures that even fine surface variations are accurately measured, which is essential for high-power laser systems and freeform optics.Given the longevity and cost of interferometers, understanding and optimizing ITF is crucial for manufacturers aiming to future-proof their optical systems.