Piezo Phase Shifter
CoreMorrow P77 piezo phase shifter
Piezo phase shifter is the most important components in phase-shifting interferometer. Piezo phase shifter is widely used due to the high resolution, fast response, easy control, and stable performance.
However, piezo ceramics also have its shortcomings, namely its nonlinearity error and small displacement, which is the reason for its wide application range.
In response to this problem, CoreMorrow designed PZT voltage drive circuit to drive the phase shift actuator to achieve phase shifting by using flexible hinge structure with amplification characteristics. Combined with optics, lower computer programming, and writing data processing programs on the software development platform, a phase shift precise control measurement device was developed.
In order to effectively solve the influence of PZT non-linearity, creep and hysteresis on phase shift accuracy, the device adopts closed-loop feedback control formed by voltage-displacement to realize adaptive micro-scale drive positioning control, which greatly improves non-linearity and reduces The external influence and interference have significantly improved the measurement accuracy of the phase shift.
CoreMorrow piezo phase shifter is driven by 3 sets of piezo stacks, which can be used for aperture lenses up to 106mm in diameter, and the displacement can reach more than 20um. Experiments have proved that the piezo phase shifter has better effect and the control precision can reach sub-nanometer level, which can greatly improve the measurement accuracy, has wide practical value in phase measurement technology, and has been widely used in various In modern interference instruments.
Laser interferometer
Piezo phase shifter for holographic interferometry
In holographic interferometry, it is necessary to determine the magnitude and direction of the displacement and deformation of the object. In the real-time detection process, it is necessary to make an immediate and rapid judgment on the direction of the displacement and deformation of the object. There are many methods for judging this, but some are more cumbersome, some are complicated, some require special equipment, others seem very unintuitive, etc., which brings a lot of inconvenience to holographic interferometry.
The piezo phase shifter can solve all the above problems.
In real-time holographic interferometry, in order to discriminate the direction of the object's displacement and deformation, piezo phase shifter is placed on the reference optical path, which is actually a small mirror that uses the piezo effect to control its spatial position. We use the phase shifter has mirror diameter of up to 106 mm and the control voltage is adjusted to move the mirror back and forth by 20 microns in the range of 0-120V. The piezoelectric phase shifter is used to change the reference optical path, and the direction of the displacement and deformation of the object is judged according to the moving direction of the interference fringe at this time. This method is simple, convenient and intuitive, and can quickly make the direction of the displacement and deformation of the object reliable. Judgment.