A5019795264- Optical Coherence Tomography Applications
- Random lasers and scattering media
- Advanced Measurement and Metrology Techniques
- Spectroscopy Techniques in Biomedical and Chemical Research
- Optical measurement and interference techniques
- Surface Roughness and Optical Measurements
- Advanced Fluorescence Microscopy Techniques
- Orbital Angular Momentum in Optics
- Advanced Fiber Optic Sensors
- Spectroscopy and Laser Applications
- Cardiovascular Health and Disease Prevention
- Metal and Thin Film Mechanics
- Optical Imaging and Spectroscopy Techniques
- Advanced Surface Polishing Techniques
- Atomic and Subatomic Physics Research
- Hemodynamic Monitoring and Therapy
- Functional Brain Connectivity Studies
- Advanced Measurement and Detection Methods
- Mechanical and Thermal Properties Analysis
- Copper Interconnects and Reliability
- Digital Holography and Microscopy
- Force Microscopy Techniques and Applications
- Advanced Optical Sensing Technologies
- Photoacoustic and Ultrasonic Imaging
- Advanced MRI Techniques and Applications
Czech Academy of Sciences, Institute of Scientific Instruments
2015-2024
Czech Academy of Sciences
2014
Abstract Light-based in-vivo brain imaging relies on light transport over large distances of highly scattering tissues. Scattering gradually reduces contrast and resolution, making it difficult to reach structures at greater depths even with the use multiphoton techniques. To deeper, minimally invasive endo-microscopy techniques have been established. These most commonly exploit graded-index rod lenses enable a variety modalities in head-fixed freely moving animals. A recently proposed...
Multimode fibres have recently been employed as high-resolution ultra-thin endoscopes, capable of imaging biological structures deep inside tissue in vivo. Here, we extend this technique to label-free non-linear microscopy with chemical contrast using coherent anti-Stokes Raman scattering (CARS) through a multimode fibre endoscope, which opens up new avenues for instant and in-situ diagnosis potentially malignant tissue. We use commercial 125 µm diameter, 0.29 NA GRIN fibre, wavefront...
Multimode fiber-based endoscopes have recently emerged as a tool for minimally invasive endoscopy in tissue, at depths well beyond the reach of multiphoton imaging. Here, we demonstrate label-free second-harmonic generation (SHG) microscopy through such fiber endoscope. We simultaneously fully control excitation polarization state and spatial distribution light tip, use this to implement polarization-resolved SHG imaging, which allows imaging identification structural proteins collagen...
Multimode fibres have recently shown promise as miniature endoscopic probes. When used for non-linear microscopy, the bandwidth of imaging system limits ability to focus light from broadband pulsed lasers well possibility wavelength tuning during imaging. We demonstrate that is limited by dispersion off-axis hologram displayed on SLM, which can be corrected for, and fibre itself. The selection therefore crucial these experiments. In addition, we show a standard prism pulse compressor...
Microendoscopes based on optical fibres have recently come to the fore as promising candidates allowing in-vivo observations of otherwise inaccessible biological structures in animal models. Despite being still its infancy, imaging can now be performed at tip a single multimode fibre, by relying powerful holographic methods for light control. Fibre endoscopy is commonly en face , resulting possible damage specimen owing direct contact between distal end probe and target. On this ground, we...
This paper deals with interference fringe center detection techniques used in low-coherence interferometry for contactless 3D inspection of macroscopic objects. It presents a complex analysis several frequently and shows their impact on the measurement accuracy. The compares those terms computational complexity, accuracy, resistance to optical dispersion caused by wedge-shaped components.
This paper presents a theoretical analysis and an experimental verification of direct method for refractive index air measurement combining low-coherence interferometry laser interferometry. The is based on monitoring optical path changes in measuring arm the Michelson interferometer caused by different environment double-spaced glass cell. article set results comparison with obtained couple reference techniques proves ability designed to measure accuracy order 10-8.
Multimode fibres show great potential for use as miniature endoscopes imaging deep in tissue with minimal damage. When used coherent anti-Stokes Raman scattering (CARS) microscopy femtosecond excitation sources, a high band-width probe is required to efficiently focus the broadband laser pulses at sample plane. Although graded-index (GRIN) have large bandwidth, it accompanied by strong background signal from four-wave mixing and other non-linear processes occurring inside fibre. We...
SignificanceOver more than 300 years, microscopic imaging keeps providing fundamental insights into the mechanisms of living organisms. Seeing structures beyond reach free-space light-based microscopy, however, requires dissection tissue—an intervention seriously disturbing its physiological functions. The hunt for low-invasiveness tools has led a growing community physicists and engineers realm complex media photonics. One activities represents exploiting multimode optical fibers (MMFs) as...
When using multimode fibers as high-resolution endoscopes, advanced adaptive optics is needed to overcome the modal dispersion which scrambles image. Additionally, for non-linear imaging methods, all wavelengths of a femtosecond laser pulse must be simultaneously focused at sample plane, with appropriate compensation, that might vary across area. We investigate bandwidth spot graded index fiber used point scanning device. demonstrate proper compensation spatial light modulator this can <45...
Advanced wavefront-shaping methods can be used to transform a simple multimode fiber into an ultra-thin laser scanning microscope. Here, we extend this technique label-free non-linear microscopy with chemical contrast using coherent anti-Stokes Raman scattering (CARS) through endoscope, which opens up new avenues for instant and in-situ diagnosis of potentially malignant tissue. We use commercial, 125 μm diameter, 0.29 NA, GRIN as the endoscopic probe. Wavefront shaping on spatial light...
The four-wave mixing background generated in a GRIN multimode fiber when performing non-linear Raman imaging reduces the image contrast. Here we demonstrate composite probe to overcome this problem.
This paper presents a contactless method for gauge blocks calibration combining laser interferometry and low-coherence interferometry. In the presented system, measurement of absolute block length is done as single-step operation without any change in optical setup during measurement, giving complete information about length. The also set optimization steps which have been order to transform original experimental into automatic system meets legal metrology requirements. To prove...
The air refractive index is an important parameter in interferometric length measurements, since it substantially affects the measurement accuracy. We present a of method based on monitoring phase difference between ambient and vacuum inside permanently evacuated double-spaced cell. cell placed one arm Michelson interferometer equipped with two light sources—red LED HeNe laser, while low-coherence laser interference signals are measured separately. Both group indices can be calculated from...
We present an experimental study of the method using a spatial light modulator for correction wavefront reflected from optically rough surface. This is based on detection mutual phase differences between different regions that correspond to constructive interference. capabilities this metrological point view ground glass samples characterized by several levels roughness. The resulting tested in dependence measurement parameters settings and verified analyzing two specific patterns generated...
In recent years, great advances have been made in developing minimal footprint micro-endoscopes using multimode optical fibres (MMF) [1]. By employing wavefront shaping methods the seemingly random speckle pattern resulting from guiding of coherent light through an MMF can be formed into a diffraction limited spot. This enables implementation multiple laser scanning techniques. this work we show that approach employed to realize label-free non-linear microscopy techniques such as anti-Stokes...
A GRIN multimode fiber (125 μm diameter, 0.29 NA) is transformed into a laser scanning microscope using wave-front shaping on an SLM. We demonstrate label-free non-linear microscopy, namely coherent anti-Stokes Raman scattering (CARS) and SHG.