Often beams, such as optical bottle beams (OBBs), possess rotational asymmetry, or other defects in the beam's intensity distribution. These beams are often due to nodal surfaces formed by the discontinuous phases which are typically necessary for the beam's unique intensity distribution. But must this always be the case? We use a combination of computational modeling with novel phase retrieval techniques and polarization-dependent vector wavefront shaping to explore the creation of computer-generated holographic beams. We discuss how to apply this method to creating obscured beams, such as uniformly enclosed optical bottle beams. and the properties these types of beams possess.
Traumatic Brain Injury (TBI) is the result of external forces impacting the brain. Despite scientific progress, TBI remains a significant cause of impairment and mortality. Recently, laser-induced shockwave (LIS) has emerged as an effective method for TBI simulation. LIS generates shockwaves through pulsed laser-induced plasma formation, allowing for the controlled study of TBI at the cellular level. This study introduces a novel approach to examine cellular morphological changes in response to shear stress, focusing on astrocyte cell type AST-1, by combining LIS with quantitative phase microscopy (QPM). QPM is a label-free technique that allows for real-time cellular dynamics observation through 3D imaging. Integrating LIS and QPM assesses astrocyte responses to shear stress caused by LIS, revealing both immediate and sustained morphological changes. Post-LIS exposure analysis shows significant alterations in astrocyte circularity, volume, surface area, and other features. Statistical tests confirm these observed trends, providing valuable insights into astrocyte responses to mechanical forces. These findings enhance our understanding of how mechanical stimuli affect astrocyte morphology, which may offer the potential for identifying and developing therapeutic strategies in TBI and related neurological disorders.
We investigate the behavior of optical vortex propagation and orbital angular momentum (OAM) conservation in scattering media by observing phase characteristics and mode content of scattered vortex beams. Micro-sized polystyrene particles in varying concentrations and optical path lengths provide a comprehensive understanding of the light dependence on optical properties and thickness of the scattering media.
Optical bottle beams (OBBs) are beams of light where a dark region is completely surrounded by light, but so far, this is not always the case. In modern OBBs, created by Bessel and vortex beams, nodal surfaces are present leading to a three-dimensional lobed structure in coherent beams. But is this always the case? We use a combination of computational modeling with novel phase retrieval techniques and polarization-dependent wavefront shaping to explore the creation of computer-generated holographic bottle beams. We discuss the creation of such beams, and how to maintain a “perfect bottle”.
Optical bottle beams (OBBs) are beams of light where a dark region is completely surrounded by light, but so far, this is not necessarily the case. In modern OBBs, created by Bessel and vortex beams, nodal surfaces are present leading to a three-dimensional lobed structure. Must this be the case? We use a combination of computational modeling with novel wavefront retrieval techniques and polarization dependent wavefront manipulation with twin spatial light modulators to explore the creation of computer-generated holographic bottle beams using various methods and whether it is possible to achieve a uniform perfectly enclosed dark region.
The conservation of optical properties of light through scattering media allows the transmission of high bandwidth information. In this work, we utilize the nonlinear self-trapping and self-guiding of a laser beam to form several centimeters long self-arranged biological waveguides in suspensions of sheep red blood cells. To increase the range of transmitted wavelength through the scattering media, a pump/probe-type nonlinear coupling has been implemented, where the self-formed waveguide conducts weaker light at different wavelengths. Finally, we demonstrate the conservation of polarization state and orbital angular momentum of the transmitted light through these biological waveguides. The ability to create waveguides and maintain optical properties after multiple scattering events may lead to improvements in communication bandwidth with low loss through scattering media and allow development of new biomedical devices.
The conservation orbital angular momentum and polarization for beams propagating through scattering bio-soft matter enables multiplexed signaling. By utilizing nonlinear optical effects in the scattering bio-soft-matter, we investigate the conservation of polarization and OAM through self-trapping and pump/probe coupled waveguides of light in sheep red blood cell suspensions at 532 nm and 780nm wavelengths. This study provides a basis for further exploration into optical signaling in soft matter systems.
Optical signaling through bio-soft matter is an emerging area of interest for biomedical applications. However, modern communication protocols require high capacity OAM, Polarisation and wavelength multiplexed signaling. Utilizing nonlinear optical effects, we investigate the conservation of polarization and orbital angular momentum through self-trapping and pump/probe coupled waveguides of light in sheep red blood cell suspensions at 532 nm and 780nm wavelengths. This study provides a basis for future exploration for signaling in soft matter systems.
There is a need for new methodologies to investigate cell apoptosis and recovery, cell adhesion, and cell-cell interactions in cellular biology and neurobiology. Such systems should be able to induce localized cell injuries and measure damage responses from single cells. In this regard, pulsed lasers can be used to produce Laser- Induced Shockwaves (LIS), which can cause cell detachments and induce cellular membrane injuries, by applying shear force in order of µN . Furthermore, since the resulting shear force can increase membrane permeability, chemicals and markers can then be transferred into cells non-invasively. Continuous-wave lasers can be used as Optical Tweezers (OT), to apply non-contact delicate forces, as low as 0.1f N , and deliver materials into cells, and also move the cells to different locations. In this paper, we introduce a combination of modalities to apply variable forces, from femto to micro newtons, to cells. Our system consists of a 1060nm continuous laser light source for OT and a 1030nm femtosecond pulsed laser for generating LIS. To have a direct measurement of changes in the cellular thickness and membrane dynamics, the cells are imaged under a Quantitative Phase Microscope (QPM). Our microscope is capable of Differential-Interference Microscopy (DIC) and Phase-Contrast microscopy (PhC) and fluorescent microscopy, making it a unique system for studying cell injuries.
The conservation of optical properties as a beam propagates through a scattering media is important to creating more complex optically induced structures and the transmission of high bandwidth information. By utilizing the nonlinear optical effect in the scattering bio-soft-matter, we investigate the conservation of polarization and orbital angular momentum through self-trapping and pump/probe coupled waveguides of light in sheep red blood cell suspensions at 532 nm and 780nm wavelengths. The ability to maintain these properties after multiple scattering events may lead to improvements in communication bandwidth with low loss.
The ability to use a wide range of wavelengths for deep penetration is important in order to target or avoid absorption bands of the biological media. By utilizing the nonlinear optical effect in the scattering bio-soft-matter, we demonstrate the self-trapping and guiding of light in sheep red blood cell suspensions for a range of different wavelengths. By pump-probe type coupling, biological waveguides formed at one wavelength can effectively guide a wide spectrum of light at low power. Finally, we investigate propagation and guiding of non-Gaussian beams in biological suspensions.
The ability to use a wide range of wavelengths for deep penetration is important in order to target or avoid absorption bands of the biological media. By utilizing the nonlinear optical effect in the scattering bio-soft-matter, we demonstrate the self-trapping and guiding of light in sheep red blood cell suspensions and bacterium suspensions for a range of different wavelengths. By master/slave-type coupling, biological waveguides formed at one wavelength can effectively guide a wide spectrum of light at low power. Finally, we investigate propagation and guiding of optical vortex beams in biological suspensions.
Using light, living cells can be manipulated to form several centimeter long waveguide structures, capable of guiding light through scattering media. Here, we will discuss some results of self-trapping and guiding of light in biological suspensions of different cells, including cyanobacteria, E. coli, and red blood cells. A forward-scattering theoretical model is developed which helps understand the experimental observations. Formed waveguides can provide effective guidance for weaker light through scattered bio-soft-matter. The ability to transmit light through turbid fluids with low loss could open up the possibilities for deep-tissue imaging, as well as noninvasive treatment and diagnostics.
Biological samples often have various absorption bands that need to be either targeted or avoided in opto-fluidic micromanipulation or biomedical imaging. With nonlinear optics, it is possible for light to self-induce a waveguide. However, the desired wavelengths may not be suitable to exhibit nonlinear self-guiding due to the absorption bands or the light-bioparticle interaction is not strong enough. Here we study formation of waveguides in red blood cell suspensions for a range of different wavelengths. We utilize nonlinear optical response for self-trapping of a laser beam, forming light guides in RBCs suspended in a phosphate buffer solution. To improve the number of usable light wavelengths over purely self-guided propagation, we use the master-slave relation, in a manner similar to the pump-probe experiment: a master beam creates a waveguide first in a scattering bio-soft-matter suspension over a few centimeters, and then a “slave” beam uses this waveguide to propagate through the medium. The slave beam, injected simultaneously, has no appreciable nonlinear self-action itself but experiences the master waveguide akin to an optical fiber. This new approach can provide a path to guide a wide range of wavelengths, including those in the absorption bands at lower power so as not to damage the sample. The fact that we can guide a wide range of wavelengths may bring about new applications in medicine and biology, for instance, in developing alternative solutions to transmit energy and information through scattering media, as needed in deep-tissue imaging, treatment and diagnostics.
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