Simple 3D Printed Microscope

Design

Professor Weinacht had several unused microscope objectives and wanted to see if it was feasible to repurpose them into a fully functional and portable microscope. Utilizing 3D printing, the project aimed to achieve two goals. First, the design need to be portable, enabling the microscope to be easily transported throughout the lab. Second, design should include the capability to capture high-quality images with a smartphone. Initial attempts to take photographs with a conventional microscope made it clear that the phone's camera required precise alignment to produce clear and undistorted images. To address this challenge, the design incorporated an adjustable phone holder, in the form of a platform, allowing users to reliably maintain the camera at the appropriate focal distance for optimal imaging. The setup is highly adjustable, allowing for both top-down and bottom-up illumination.

Hover over the image for more information about each component.

Magnification

The maximum predicted magnification of the microscope is 100x, based on the combination of a 10x objective and a 10x eyepiece. While theoretical calculations can provide this estimate, experimentally the true magnification is expected to be lower. By comparing images taken through the microscope to a reference image of a ruler without magnification, the effective magnification was estimated to be approximately 70x. This discrepancy may result from the distance from the objective and the eyepiece deviating from ideal. However, we know the magnification is comparable to other setups as some online sources suggest that a field of view (FOV) of around 2 mm is typical for a microscope operating at 100x magnification. Knowing the FOV enables the estimation of sizes within the image, such as the sizes of defects.

Looking Through the Scope

We observed an AMO sample under the microscope using both top-down and bottom-up illumination techniques. The results demonstrated excellent resolution, with fine details clearly visible. Notably, the choice of illumination style revealed additional details; for instance, the defect shown in the third image is only visible with bottom-up illumination, highlighting the importance of being able to adjust the angle of illumination in the setup.

Top Down Pciture of AMO

Top Down Picture of AMO

Bottom Up Picture of AMO

Microscope Visualization of Defects in an Acousto-Optic Modulator (AOM)

Using the microscope, we identified the cause of a defective AOM. In our lab, the AOM is used in a pulse shaper to spread the colors of an ultrafast laser pulse into a stripe of light across its wide aperture. An acoustic wave generates a diffracted optical beam that exits at a slight angle relative to the incident beam, forming an interference pattern within the AOM, similar to the pattern created by two plane waves propagating at a slight angle. The AOM was found to be defective after a diffraction pattern was observed even in the absence of an acoustic wave.

Microscopic analysis revealed a pattern whose spacing closely matched the wavelength of the acoustic wave used in the AOM (calculated to be approximately 40 µm based on the 150 MHz acoustic frequency). This finding attributed the defect to the formation of color centers, which arise over time as ithe maxima generated by the constructive interference of the ntense UV light generates a diffraction pattern that slightly darkens regions of the AOM and alters the refractive index locally. These color centers then orm a grating pattern with a periodicity matching that of the original acoustic wave.

This application demonstrates the microscope's utility in diagnosing and analyzing material defects in the lab.

Student Biography

My name is Rahul Menon, and I'm an undergraduate student majoring in Physics with a minor in Chemistry at Stony Brook University. I hope to pursue a career in medicine and use physics to advance neurology. Over the past year, I have focused on projects involving 3D printing within our research group. During my first semester, I designed a 3D-printed mirror mount, and this semester, I developed a partially 3D-printed microscope tailored for laboratory use.

Outside of academics, I enjoy chess, hiking, and traveling.

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