A5082800015- Advanced Fluorescence Microscopy Techniques
- Laser-Matter Interactions and Applications
- Photoreceptor and optogenetics research
- Advanced Fiber Laser Technologies
- Laser-Plasma Interactions and Diagnostics
- Cell Image Analysis Techniques
- Electrowetting and Microfluidic Technologies
- Neuroscience and Neural Engineering
- Optical Coherence Tomography Applications
- Spectroscopy Techniques in Biomedical and Chemical Research
- Spectroscopy and Quantum Chemical Studies
- Analytical Chemistry and Sensors
- Olfactory and Sensory Function Studies
- Neuroscience and Neuropharmacology Research
- Image Processing Techniques and Applications
- Optical Imaging and Spectroscopy Techniques
- Solid State Laser Technologies
- Biosensors and Analytical Detection
- Photorefractive and Nonlinear Optics
- Microfluidic and Capillary Electrophoresis Applications
- Photoacoustic and Ultrasonic Imaging
- Microfluidic and Bio-sensing Technologies
- Glaucoma and retinal disorders
- Retinal Development and Disorders
- Photonic and Optical Devices
University of Colorado Denver
2013-2024
University of Colorado Anschutz Medical Campus
2015-2024
The University of Queensland
2022-2023
Arc Research Institute
2023
Palo Alto Institute
2023
University of Alabama
2022
Baylor University
2022
UNSW Sydney
2021
University of California, Berkeley
2003-2020
University of Denver
2018
We demonstrate enhanced generation of coherent light in the "water window" region soft x-ray spectrum at 4.4 nanometers, using quasi-phase-matched frequency conversion ultrafast laser pulses. By periodically modulating diameter a gas-filled hollow waveguide, phase mismatch normally present between and generated can be partially compensated. This makes it possible to use neon gas as nonlinear medium coherently convert up water window, illustrating that techniques optics applied effectively...
We present a miniature head mounted two-photon fiber-coupled microscope (2P-FCM) for neuronal imaging with active axial focusing enabled using electrowetting lens. show three-dimensional of structure and record activity from GCaMP6s fluorescence multiple focal planes in freely-moving mouse. Two-color simultaneous GFP tdTomato is also demonstrated. Additionally, dynamic control the scanning lens allows tilting plane enabling neurons depths to be imaged single plane. Two-photon increased...
We demonstrate the generation of very high-order harmonics, up to 250 eV, using argon gas. This extends by 100 eV highest harmonics previously observed Ar and exceeds energies any other medium besides helium. advance is made possible a waveguide geometry limit plasma-induced laser beam defocusing, making it generate high from ions. work shows that harmonic emission ions can extend laser-based coherent up-conversion into soft x-ray region spectrum.
We present a high-resolution miniature, light-weight fluorescence microscope with electrowetting lens and onboard CMOS for high resolution volumetric imaging structured illumination rejection of out-of-focus scattered light. The miniature (SIMscope3D) delivers light using coherent fiber bundle to obtain optical sectioning an axial 18 µm. Volumetric eGFP labeled cells in fixed mouse brain tissue at depths up 260 µm is demonstrated. functionality SIMscope3D provide background free 3D shown by...
We present the first demonstration of a new mechanism for temporal compression ultrashort light pulses that operates at high (i.e., ionizing) intensities. By propagating inside hollow waveguide filled with low-pressure argon gas, we demonstrate self-compression from 30 to 13 fs, without need any external dispersion compensation. Theoretical models show 3D spatiotemporal reshaping pulse due combination ionization-induced spectral broadening, plasma-induced refraction, and guiding in are...
Increasing interest in the role of lipids cancer cell proliferation and resistance to drug therapies has motivated need develop better tools for cellular lipid analysis. Quantification cells is typically done by destructive chromatography protocols that do not provide spatial information on distribution prevent dynamic live studies. Methods allow analysis content are therefore great importance. Using micro-Raman spectroscopy coherent anti-Stokes Raman scattering (CARS) microscopy, we...
We report a miniature, lightweight fiber-coupled confocal fluorescence microscope that incorporates an electrowetting variable focus lens to provide axial scanning for full three-dimensional (3D) imaging. Lateral is accomplished by coupling our device laser-scanning through coherent imaging fiber-bundle. The optical components of the are combined in custom 3D-printed adapter with assembled weight <2 g can be mounted onto head mouse. Confocal sectioning provides resolution ∼12 μm and scan...
We review multiphoton microscopy (MPM) including two-photon autofluorescence (2PAF), second harmonic generation (SHG), third (THG), fluorescence lifetime (FLIM), and coherent anti-Stokes Raman Scattering (CARS) with relevance to clinical applications in ophthalmology. The different imaging modalities are discussed highlighting the particular strength that each has for functional tissue imaging. MPM is compared current ophthalmological techniques such as reflectance confocal microscopy,...
Coherent beams at soft X-ray (SXR) wavelengths can be generated using extreme nonlinear optics by focusing an intense laser into a gas. In this paper, we discuss phase-matching and quasi-phase-matching techniques that use gas-filled modulated waveguides to enhance the frequency conversion process. This leads generation of SXR are both spatially temporally coherent.
Efficient reflection grisms for pulse-compression and material-dispersion compensation have been designed demonstrated in a 40 fs, 300 μJ, 5 kHz downchirped pulse amplification system the first time to our knowledge. A grism design 800nm femtosecond laser dispersion applications is realized by using standard, commercial diffraction gratings.
A simple fabrication technique to create all silicon/glass microfluidic devices is demonstrated using femtosecond laser ablation and anodic bonding. In a first application, we constructed cell counting device based on small angle light scattering. The counter featured embedded optical fibers for multiangle excitation detection of scattered and/or fluorescence. performance the was benchmarked against commercial fluorescence-activated sorter.
Laser scanners are an integral part of high resolution biomedical imaging systems such as confocal or 2-photon excitation (2PE) microscopes. In this work, we demonstrate the utility electrowetting on dielectric (EWOD) prisms a lateral laser-scanning element integrated in conventional 2PE microscope. To best our knowledge, is first demonstration for EWOD prisms. devices provide transmissive, low power consuming, and compact alternative to adaptive optics, hence technology has tremendous...
Abstract The cerebellum plays a crucial role in sensorimotor and associative learning. However, the contribution of molecular layer interneurons (MLIs) to these processes is not well understood. We used two-photon microscopy study ensembles cerebellar MLIs go-no go task where mice obtain sugar water reward if they lick spout presence rewarded odorant avoid timeout when refrain from licking for unrewarded odorant. In naive animals MLI responses did differ between odorants. With learning,...
A feature issue is being presented by a team of guest editors containing papers based on contributed submissions including studies at Optics and the Brain, held April 24-27, 2023 as part Optica Biophotonics Congress: in Life Sciences, Vancouver, Canada.
We demonstrate a novel electrowetting liquid combination using room temperature ionic (RTIL) and nonpolar liquid, 1-phenyl-1-cyclohexene (PCH) suitable for focus-tunable 3-photon microscopy. show that both liquids have over 90% transmission at 1300 nm 1.1 mm pathlength an index of refraction contrast 0.123. A lens these can be tuned from contact angle 133 to 48° with applied voltages 0 60 V, respectively. Finally, three-photon imaging system including RTIL was used image mouse brain slice....
Optical sectioning structured illumination microscopy (OS-SIM) provides optical capability in wide-field microscopy. The required patterns have traditionally been generated using spatial light modulators (SLM), laser interference patterns, or digital micromirror devices (DMDs) which are too complex to implement miniscope systems. MicroLEDs emerged as an alternative source for patterned due their extreme brightness and small emitter sizes. This paper presents a directly addressable striped...
The ER plays a fundamental role in storing cellular Ca2+, generating Ca2+ signals, and modulating both the cytosol mitochondria. Genetically encoded sensors can be explicitly targeted to directly define levels monitor fluxes of within this organelle. In study we use an ER-targeted sensor level dynamics cells expressing mutant presenilin proteins. Growing evidence suggests enigmatic presenilin-1 regulating Ca2+. Presenilin-1 was initially identified screen for genetic causes inherited...
The development of technologies to characterize the ocular aqueous outflow system (AOS) is important for understanding pathophysiology glaucoma. Multiphoton microscopy (MPM) offers advantage high-resolution, label-free imaging with intrinsic image contrast because emitted signals result from specific biomolecular content tissue. Previous attempts use MPM murine irido-corneal region directly through sclera have suffered degradation in resolution due scattering focused laser light. As a...
We present numerical simulations of multielectrode electrowetting devices used in a novel optical design to correct wavefront aberration. Our system consists two devices, preceded by single fixed lens. The elements function as adaptive that can be aberrations inherent many imaging setups, biological samples, and the atmosphere. are able accurately simulate liquid-liquid interface shape using computational fluid dynamics. Ray tracing analysis these surfaces shows clear evidence aberration...
We present results for a new type of fiber-coupled stimulated emission depletion (STED) microscope which uses single fiber to transport STED and excitation light, as well collect the fluorescence signal. Our method utilizes two higher-order eigenmodes polarization maintaining (PM) generate doughnut-shaped beam. The modes are excited with separate beams that share no temporal coherence, yielding output is independent bending. measured resolution using 45 nm fluorescent beads found median bead...
Abstract Vagus nerve stimulation has shown many benefits for disease therapies but current approaches involve imprecise electrical that gives rise to off-target effects, while the functionally relevant pathways remain poorly understood. One method overcome these limitations is use of optogenetic techniques, which facilitate targeted neural communication with light-sensitive actuators (opsins) and can be organs interest based on location viral delivery. Here, we tested whether retrograde...