More Like this

1. Deep-3D microscope: 3D volumetric microscopy of thick scattering samples using a wide-field microscope and machine learning

   https://doi.org/10.1364/BOE.444488  

   Li, Bowen; Tan, Shiyu; Dong, Jiuyang; Lian, Xiaocong; Zhang, Yongbing; Ji, Xiangyang; Veeraraghavan, Ashok (December 2021, Biomedical Optics Express)

   Confocal microscopy is a standard approach for obtaining volumetric images of a sample with high axial and lateral resolution, especially when dealing with scattering samples. Unfortunately, a confocal microscope is quite expensive compared to traditional microscopes. In addition, the point scanning in confocal microscopy leads to slow imaging speed and photobleaching due to the high dose of laser energy. In this paper, we demonstrate how the advances in machine learning can be exploited to teach a traditional wide-field microscope, one that’s available in every lab, into producing 3D volumetric images like a confocal microscope. The key idea is to obtain multiple images with different focus settings using a wide-field microscope and use a 3D generative adversarial network (GAN) based neural network to learn the mapping between the blurry low-contrast image stacks obtained using a wide-field microscope and the sharp, high-contrast image stacks obtained using a confocal microscope. After training the network with widefield-confocal stack pairs, the network can reliably and accurately reconstruct 3D volumetric images that rival confocal images in terms of its lateral resolution, z-sectioning and image contrast. Our experimental results demonstrate generalization ability to handle unseen data, stability in the reconstruction results, high spatial resolution even when imaging thick (∼40 microns) highly-scattering samples. We believe that such learning-based microscopes have the potential to bring confocal imaging quality to every lab that has a wide-field microscope. 

   more » « less
2. All-reflective freeform microscope objective for ultra-broadband microscopy

   https://doi.org/10.1364/OE.544492  

   Bauer, Aaron; Rolland, Jannick_P; Clark, Stephan; Potma, Eric; Hanninen, Adam (December 2024, Optics Express)

   Conventional refractive microscope objective lenses have limited applicability to a range of imaging modalities due to the dispersive nature of their optical elements. Designing a conventional refractive microscope objective that provides well-corrected imaging over a broad spectral range can be challenging, if not impossible. In contrast, reflective optics are inherently achromatic, so a system composed entirely of reflective elements is free from chromatic aberrations and, as a result, can image over an ultra-wide spectral range with perfect color correction. This study explores the design space of unobscured high numerical aperture, all-reflective microscope objectives. In particular, using freeform optical elements we obviate the need for a center obscuration, rendering the objective’s modulation transfer function comparable to that of refractive lens systems of similar numerical aperture. We detail the design process of the reflective objective, from determining the design specifications to the system optimization and sensitivity analysis. The outcome is an all-reflective freeform microscope objective lens with a 0.65 numerical aperture that provides diffraction-limited imaging and is compatible with the geometric constraints of commercial microscope systems. 

   more » « less
3. The Visible Microscope

   https://doi.org/10.18130/V3/K9TGP4  

   Watts, Jo; Bull, Glen; Watts, Jo (March 2024, National Technology Leadership Society)

   The Visible Microscope is inspired by the OpenFlexure microscope. The Open Flexure microscope is a laboratory-grade microscope constructed using 3D printed parts and a single-board computer that is widely used in research laboratories internationally (Sharkey, Foo, Kabla, Baumberg & Bowman, 2016). The Visible Microscope is an adapted version of the Open Flexure microscope designed for K-12 schools. 

   more » « less
4. A low-cost confocal microscope for the undergraduate lab

   https://doi.org/10.1119/5.0128277  

   Reguilon, A.; Bethard, W.; Brekke, E. (May 2023, American Journal of Physics)

   We demonstrate a simple and cost-efficient scanning confocal microscope setup for use in advanced instructional physics laboratories. The setup is constructed from readily available commercial products, and the implementation of a 3D-printed flexure stage allows for further cost reduction and pedagogical opportunity. Experiments exploring the thickness of a microscope slide and the surface of solid objects with height variation are presented as foundational components of undergraduate laboratory projects and demonstrate the capabilities of a confocal microscope. This system allows observation of key components of a confocal microscope, including depth perception and data acquisition via transverse scanning, making it an excellent pedagogical resource. 

   more » « less
5. Biodynamic digital holographic speckle microscopy for oocyte and embryo metabolic evaluation

   https://doi.org/10.1364/AO.404298  

   Li, Zhe; Lorenzo-Lorenzo, Ilka_M; An, Ran; Turek, John; Nolte, David_D; Machaty, Zoltan (November 2020, Applied Optics)

   Assisted reproductive technologies seek to improve the success rate of pregnancies. Morphology scoring is a common approach to evaluate oocyte and embryo viability prior to embryo transferin utero, but the efficacy of the method is low. We apply biodynamic imaging, based on dynamic light scattering and low-coherence digital holography, to assess the metabolic activity of oocytes and embryos. A biodynamic microscope, developed to image small and translucent biological specimens, is inserted into the bay of a commercial inverted microscope that can switch between conventional microscopy channels and biodynamic microscopy. We find intracellular Doppler spectral features that act as noninvasive proxies for embryo metabolic activity that may relate to embryo viability. 

   more » « less