Testing process in industrial profiling depends on the characterization of 3D objects with high-sensitivity in spatial and temporal domains. Ordinary 3D measurement instruments scan the image area in the temporal domain; therefore, these techniques experience low temporal stability especially for industrial and biomedical sensing. We propose a novel scan-free extended image instrument for sensing area of 3D microscopic objects using an interferometric technique with fixed optical parameters, such as resolution, and without mechanical movement. The technique could accelerate the control process in industrial fault detection and images of biological samples could be obtained in a shorter time. First, a stable system for doubling the image area is introduced. Second, the principles underlying the 2D sampling scheme are introduced to record the maximum image area using a dual multiplexing technique at sub-sampling frequency. Moreover, a standard factor is presented as a figure of merit to determine the exact image area enhancement. Finally, the feasibility of this technique was demonstrated by sensing reflective and transparent objects with image area of up to 4.3-times that of a single hologram recording using the square scheme. Furthermore, scan-free monitoring of photolithography process was demonstrated in real-time. The standard deviation of thickness is 0.48-nm, which demonstrates the sub-nanometer temporal sensitivity of this technique.
- Image sampling
- phase detection
- shape control
ASJC Scopus subject areas
- Control and Systems Engineering
- Electrical and Electronic Engineering