Large zooming range adaptive microscope employing tunable objective and eyepiece

Abstract

The conventional microscope has discrete magnification and slow response time in zoom process, which is difficult to capture the dynamic activity of the live specimen. We demonstrate an adaptive microscope employing a tunable objective and a tunable eyepiece with large zooming range. The tunable objective consists of three glass lenses and four electrowetting liquid lenses. The tunable eyepiece consists of an achromatic eyepiece and an electrowetting liquid lens. The focal point between the objective and the eyepiece is designed to be tunable, which are controlled by voltages. Thus, the tuning range is relatively large. We fabricate the adaptive microscope and observe the specimen. In the experiment, the magnification of the microscope changes continuously from ~ 59.1 × to ~ 159.2 × , and the largest numerical aperture is ~ 0.212. The tunable eyepiece can release the back focal length of the tunable objective, which increases the zoom range of the microscope. No mechanical movement is required and the aberrations can be corrected over a wide wavelength range. Thus, the proposed adaptive microscope has a potential application in biological research and clinical medical examination. Microscopes play an important role in scientific research and production, such as physiological applications 1 , biomedical engineering 2 and microfabrication 3. For targets of different sizes, microscopes need different magnifications. Besides, to observe large area of cells and a zoom-in area with high resolution, the higher requirements of real-time observation and continuous zoom change on microscopes emerges 4. The conventional microscopes can change magnifications by manually converting objectives. But its magnifications are not continuous and the conversion operation introduces sample vibration. One of the solutions for continuous zoom change is to use the mechanical or optical compensation system driven by mechanical movement 5,6. However, such compensation systems are bulky and sample vibration is still an issue due to the mechanical movement. Besides the slow zoom speed affects the real-time observation. Fortunately, the liquid lenses have changed the traditional lens systems 7. Due to lightweight, low power consumption and fast response speed, liquid lenses have important applications in imaging 8-10 , display 11 , and communication 12. Moreover, liquid lenses are wildly used in microscopy as focusing component for axial scanning 13-16 , increasing the depth-of-field 17,18 and autofocusing 19,20. However, they cannot achieve continuous zoom change. For example, a five-dimensional microscopy using liquid lens is proposed and able to scan volumes rapidly and reproducibly 21. This microscopy has fast scan speed however it cannot zoom continuously. A adaptive microscope objective using liquid lens is proposed 22. The magnification of the adaptive microscope objective tune from ~ 7.8 × to ~ 13.2 × , but its zoom range is very limited due to fixed back focal length (BFL). Therefore, it is still urgent to study microscopes with larg...

Deep Learning Enables Optofluidic Zoom System with Large Zoom Ratio and High Imaging Resolution

“…Optical zoom systems based on an electrowetting liquid lens have become a research hotspot in the field of optics. Many zoom systems based on electrowetting liquid lenses have been proposed [ 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. For example, a two-liquid-lenses zoom system was proposed, in which a zoom factor of 1.8 was implemented [ 7 ].…”