-
Nature Methods Apr 2021
Topics: Germanium; Kinesins; Nanospheres; Optical Tweezers; Optics and Photonics
PubMed: 33828268
DOI: 10.1038/s41592-021-01121-7 -
Small (Weinheim An Der Bergstrasse,... Sep 2021Micromanipulation techniques that are capable of assembling nano/micromaterials into usable structures such as topographical micropatterns (TMPs) have proliferated...
Micromanipulation techniques that are capable of assembling nano/micromaterials into usable structures such as topographical micropatterns (TMPs) have proliferated rapidly in recent years, holding great promise in building artificial electronic and photonic microstructures. Here, a method is reported for forming TMPs based on optoelectronic tweezers in either "bottom-up" or "top-down" modes, combined with in situ photopolymerization to form permanent structures. This work demonstrates that the assembled/cured TMPs can be harvested and transferred to alternate substrates, and illustrates that how permanent conductive traces and capacitive circuits can be formed, paving the way toward applications in microelectronics. The integrated, optical assembly/preservation method described here is accessible, versatile, and applicable for a wide range of materials and structures, suggesting utility for myriad microassembly and microfabrication applications in the future.
Topics: Electronics; Micromanipulation; Optics and Photonics; Photons
PubMed: 34390185
DOI: 10.1002/smll.202103702 -
Optics Letters Jun 2023Quantitative phase microscopy (QPM) literally images the quantitative phase shift associated with image contrast, where the phase shift can be altered by laser heating....
Quantitative phase microscopy (QPM) literally images the quantitative phase shift associated with image contrast, where the phase shift can be altered by laser heating. In this study, the thermal conductivity and thermo-optic coefficient (TOC) of a transparent substrate are simultaneously determined by measuring the phase difference induced by an external heating laser using a QPM setup. The substrates are coated with a 50-nm-thick titanium nitride film to photothermally generate heat. Then, the phase difference is semi-analytically modeled based on the heat transfer and thermo-optic effect to simultaneously extract the thermal conductivity and TOC. The measured thermal conductivity and TOC agree reasonably well, indicating the potential for measuring the thermal conductivities and TOCs of other transparent substrates. The concise setup and simple modeling differentiate the advantages of our method from other techniques.
Topics: Microscopy; Optics and Photonics; Lasers; Thermal Conductivity
PubMed: 37319089
DOI: 10.1364/OL.489182 -
Advanced Biology Apr 2022The maker movement has reached the optics labs, empowering researchers to create and modify microscope designs and imaging accessories. 3D printing has a disruptive... (Review)
Review
The maker movement has reached the optics labs, empowering researchers to create and modify microscope designs and imaging accessories. 3D printing has a disruptive impact on the field, improving accessibility to fabrication technologies in additive manufacturing. This approach is particularly useful for rapid, low-cost prototyping, allowing unprecedented levels of productivity and accessibility. From inexpensive microscopes for education such as the FlyPi to the highly complex robotic microscope OpenFlexure, 3D printing is paving the way for the democratization of technology, promoting collaborative environments between researchers, as 3D designs are easily shared. This holds the unique possibility of extending the open-access concept from knowledge to technology, allowing researchers everywhere to use and extend model structures. Here, it is presented a review of additive manufacturing applications in optical microscopy for life sciences, guiding the user through this new and exciting technology and providing a starting point to anyone willing to employ this versatile and powerful new tool.
Topics: Biological Science Disciplines; Microscopy; Optics and Photonics; Printing, Three-Dimensional
PubMed: 34693666
DOI: 10.1002/adbi.202100994 -
Journal of Biomedical Optics Jun 2021Guest editors Jessica Ramella-Roman, Amir H. Gandjbakhche, Stephen C. Kanick, Babak Shadgan, and Bruce J. Tromberg introduce and summarize the articles included in the...
Guest editors Jessica Ramella-Roman, Amir H. Gandjbakhche, Stephen C. Kanick, Babak Shadgan, and Bruce J. Tromberg introduce and summarize the articles included in the 6-part JBO Special Section on Wearable, Implantable, Mobile, and Remote Biomedical Optics Photonics.
Topics: Histological Techniques; Optics and Photonics; Prostheses and Implants; Wearable Electronic Devices
PubMed: 34189875
DOI: 10.1117/1.JBO.26.6.062701 -
Ophthalmic & Physiological Optics : the... Sep 2021
Topics: Eye; Humans; Optics and Photonics
PubMed: 34387914
DOI: 10.1111/opo.12871 -
Nature Protocols Dec 2023Two-photon microscopy, combined with the appropriate optical labelling, enables the measurement and tracking of submicrometer structures within brain cells, as well as... (Review)
Review
Two-photon microscopy, combined with the appropriate optical labelling, enables the measurement and tracking of submicrometer structures within brain cells, as well as the spatiotemporal mapping of spikes in individual neurons and of neurotransmitter release in individual synapses. Yet, the spatial resolution of two-photon microscopy rapidly degrades as imaging is attempted at depths of more than a few scattering lengths into tissue, i.e., below the superficial layers that constitute the top 300-400 µm of the neocortex. To obviate this limitation, we shape the focal volume, generated by the excitation beam, by modulating the incident wavefront via guidestar-assisted adaptive optics. Here, we describe the construction, calibration and operation of a two-photon microscope that incorporates adaptive optics to restore diffraction-limited resolution at depths close to 900 µm in the mouse cortex. Our setup detects a guidestar formed by the excitation of a red-shifted dye in blood serum, used to directly measure the wavefront. We incorporate predominantly commercially available optical, optomechanical, mechanical and electronic components, and supply computer-aided design models of other customized components. The resulting adaptive optics two-photon microscope is modular and allows for expanded imaging and optical excitation capabilities. We demonstrate our methodology in the mouse neocortex by imaging the morphology of somatostatin-expressing neurons that lie 700 µm beneath the pia, calcium dynamics of layer 5b projection neurons and thalamocortical glutamate transmission to L4 neurons. The protocol requires ~30 d to complete and is suitable for users with graduate-level expertise in optics.
Topics: Mice; Animals; Microscopy; Optics and Photonics; Photons; Neurons; Calcium
PubMed: 37914781
DOI: 10.1038/s41596-023-00893-w -
Nano Letters Sep 2021Two-dimensional transition metal dichalcogenides are promising candidates for ultrathin light modulators due to their highly tunable excitonic resonances at visible and...
Two-dimensional transition metal dichalcogenides are promising candidates for ultrathin light modulators due to their highly tunable excitonic resonances at visible and near-infrared wavelengths. At cryogenic temperatures, large excitonic reflectivity in monolayer molybdenum diselenide (MoSe) has been shown, but the permittivity and index modulation have not been studied. Here, we demonstrate large gate-tunability of complex refractive index in monolayer MoSe by Fermi level modulation and study the doping dependence of the A and B excitonic resonances for temperatures between 4 and 150 K. By tuning the charge density, we observe both temperature- and carrier-dependent epsilon-near-zero response in the permittivity and transition from metallic to dielectric near the A exciton energy. We attribute the dynamic control of the refractive index to the interplay between radiative and non-radiative decay channels that are tuned upon gating. Our results suggest the potential of monolayer MoSe as an active material for emerging photonics applications.
Topics: Molybdenum; Optics and Photonics; Refractometry; Temperature; Transition Elements
PubMed: 34468150
DOI: 10.1021/acs.nanolett.1c02199 -
Sensors (Basel, Switzerland) Aug 2019The past decades have witnessed the rapid development in soft, stretchable, and biocompatible devices for applications in biomedical monitoring, personal healthcare, and... (Review)
Review
The past decades have witnessed the rapid development in soft, stretchable, and biocompatible devices for applications in biomedical monitoring, personal healthcare, and human-machine interfaces. In particular, the design of soft devices in optics has attracted tremendous interests attributed to their distinct advantages such as inherent electrical safety, high stability in long-term operation, potential to be miniaturized, and free of electromagnetic interferences. As the alternatives to conventional rigid optical waveguides, considerable efforts have been made to develop light-guiding devices by using various transparent and elastic polymers, which offer desired physiomechanical properties and enable wearable/implantable applications in optical sensing, diagnostics, and therapy. Here, we review recent progress in soft and stretchable optical waveguides and sensors, including advanced structural design, fabrication strategies, and functionalities. Furthermore, the potential applications of those optical devices for various wearable and biomedical applications are discussed. It is expected that the newly emerged soft and stretchable optical technologies will provide a safe and reliable alternative to next-generation, smart wearables and healthcare devices.
Topics: Biocompatible Materials; Humans; Hydrogels; Man-Machine Systems; Monitoring, Physiologic; Optics and Photonics; Polymers; Prostheses and Implants; Robotics; Wearable Electronic Devices
PubMed: 31480393
DOI: 10.3390/s19173771 -
Annual Review of Biomedical Engineering Jun 2020Super-resolution microscopy techniques are versatile and powerful tools for visualizing organelle structures, interactions, and protein functions in biomedical research.... (Review)
Review
Super-resolution microscopy techniques are versatile and powerful tools for visualizing organelle structures, interactions, and protein functions in biomedical research. However, whole-cell and tissue specimens challenge the achievable resolution and depth of nanoscopy methods. We focus on three-dimensional single-molecule localization microscopy and review some of the major roadblocks and developing solutions to resolving thick volumes of cells and tissues at the nanoscale in three dimensions. These challenges include background fluorescence, system- and sample-induced aberrations, and information carried by photons, as well as drift correction, volume reconstruction, and photobleaching mitigation. We also highlight examples of innovations that have demonstrated significant breakthroughs in addressing the abovementioned challenges together with their core concepts as well as their trade-offs.
Topics: Animals; Astigmatism; Coma; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Mice; Microscopy; Microscopy, Confocal; Microscopy, Fluorescence; Models, Statistical; Optics and Photonics; Organelles; Photobleaching; Photons
PubMed: 32243765
DOI: 10.1146/annurev-bioeng-060418-052203