High-precision objective wavefront detection challenge overcome! FIS4 dual-solution unveils a new paradigm for optical inspection.

Traditional interferometry faces three major challenges: sensitivity to environmental vibrations, complex optical paths, and cumbersome phase shifting. The FIS4 wavefront sensor, with its four-wave shearing interferometry technology, single-optical-path design, and real-time wavefront reconstruction algorithm, fundamentally solves these problems, making it possible to achieve laboratory-level accuracy in industrial settings.

Technological Breakthrough: FIS4's Core Advantages

The FIS4 wavefront sensor is based on four-wave shearing interferometry and employs a single-optical-path design, eliminating the need for a reference optical path and fundamentally simplifying the optical path structure. Its common-path design makes the system extremely insensitive to environmental vibrations, maintaining nanometer-level stability even in industrial environments without vibration isolation platforms. More importantly, FIS4 utilizes a real-time wavefront reconstruction algorithm, eliminating the cumbersome phase-shifting process of traditional interferometers and directly acquiring complete phase information, resulting in a several-fold increase in measurement efficiency.

Detailed Explanation of Two Objective Lens Testing Schemes

Option 1: Standard spherical mirror method

The optical path diagram of test scheme 1 is shown in Figure 2: The laser emitted by the laser enters the objective lens under test after passing through the beam expander and beam splitter. The objective lens under test converges the beam to coincide with the center of the standard spherical mirror. The beam returns along the original path through the standard spherical mirror and then passes through the objective lens under test and beam splitter in sequence to enter the FIS4 wavefront sensor for wavefront measurement.

The core advantage of this approach lies in its systematic error calibration function. By pre-calibrating the incident light path using a standard plane mirror (Figure 3), FIS4 can store systematic error data. During actual measurements, the software automatically subtracts systematic errors, thereby accurately extracting the true wavefront information of the objective lens under test.

Option 2: Ideal Spherical Wave Method

The optical path diagram of test scheme 2 is shown in Figure 4. After the laser beam is expanded, it is focused by a converging lens and focused onto a small aperture. After passing through the small aperture, an ideal spherical wave is generated, which then passes through the objective lens under test and enters the FIS4 wavefront sensor for wavefront measurement.

This method generates an ideal spherical wave through a pinhole, allowing direct testing of the objective lens. The key lies in the precise alignment of the pinhole position with the objective lens's focal point; FIS4's real-time Zernike coefficient analysis function provides a perfect solution for this.

The technological advantages of FIS4 in objective lens inspection:

✅ Superior vibration resistance

Common-path design ensures<5nm fluctuation in industrial vibration environments

No vibration isolation platform required; laboratory-level accuracy achieved on-site.

✅ Real-time guidance for assembly and adjustment

Real-time Zernike coefficient analysis provides intuitive guidance for optical adjustment

Minimized defocus term ensures precise objective lens focus positioning.

✅ High-efficiency measurement

Millisecond-level wavefront reconstruction eliminates traditional phase-shifting waiting time.

Real-time output of key parameters such as PV, RMS, PSF, MTF, and Zernike coefficients.

A breakthrough in domestically produced high-end instruments

Since 2006, Professor Yang Yongying's team at Zhejiang University has spent 17 years developing and launching the wide-spectrum FIS4 series wavefront sensor, entirely domestically developed, achieving technological superiority over a certain French wavefront sensor with a consistency greater than 99%!

FIS4 Wavefront Sensor  not only excels in objective lens inspection but also boasts mature application solutions in high-end optical manufacturing fields such as freeform surfaces, aspherical surfaces, and space optical systems. We provide comprehensive technical support, from pre-sales solution design to after-sales technical support, ensuring users receive the best experience.

We welcome experts and scholars requiring objective wavefront inspection to collaborate with our technical team. We offer trial inspection services and customized solutions.