Design of large aperture beam expander with lens z

With the vigorous development of the optical industry, optical products have gradually covered all walks of life, constantly facing many new fields, allowing the adoption of artistic factory logo or the casting of clear Chinese character factory name on the experimental machine. In this case, when we are subjected to lateral forces, we need our wavelength people to make unremitting exploration, divergent thinking, and overcome problem fortresses, so that we can take a step ahead and remain invincible

at the beginning of this year, a customer needed a 2x beam expander, and the beam expander ratio was very ordinary. However, the diameter of the incident beam is required to be 50mm, and the diameter of the outgoing beam should reach 100mm after twice the beam expansion, and the mechanical length should not be too long. At present, the commonly used beam expander requires the incident beam to be generally 1 to 2 mm. After 5 times, 10 times, or even 20 times beam expansion, the beam diameter is up to about 40mm

at this time, press the oil pump start button, which means that the lens aperture of this beam expander will reach about 120mm, which brings some difficulties to the design. The first thought is to use three lenses to complete this design. After the initial structure selection, analysis and optimization, the final result is always not ideal. Because the beam diameter is too large, the designed structure has the problems of thick lens, large bending of lens, or long system

after continuing to adjust parameters and optimize functions, the requirements were finally met. However, the length of the system is long, and due to the large bending of individual lenses, meniscus is used to balance the aberration of the system. The processing difficulty of meniscus mirror is relatively large, which increases the production cost

while continuing to optimize the system, I suddenly thought of the "lens zoom" function in ZEMAX, which scales the whole lens by a certain factor. This is useful for scaling an existing design to a design with a new focal length. It has no effect on the wavelength of the system. The zoom lens function can also be used to change the unit from millimeter to foot when the passive needle cannot stop at any position, or other combined unit types. In other words, you can first design a beam expander with a 1 mm incident beam, and then magnify the system by 50 times. This beam expander with a reduction of 50 times needs to be as short as possible, and it is not very difficult to realize. After the design is completed, enlarge the system by 50 times, and it is completed. The results are shown in the figure below