A5009321969- Laser Material Processing Techniques
- Advanced Fiber Optic Sensors
- Advanced Fiber Laser Technologies
- Photonic and Optical Devices
- Photonic Crystal and Fiber Optics
- Orbital Angular Momentum in Optics
- Laser-Matter Interactions and Applications
- Advanced Surface Polishing Techniques
- Nonlinear Optical Materials Studies
- Microfluidic and Bio-sensing Technologies
- Photorefractive and Nonlinear Optics
- Near-Field Optical Microscopy
- Laser-induced spectroscopy and plasma
- Photonic Crystals and Applications
- Glass properties and applications
- Solid State Laser Technologies
- Silicon Nanostructures and Photoluminescence
- Semiconductor Lasers and Optical Devices
- Optical Network Technologies
- Particle Dynamics in Fluid Flows
- Quantum optics and atomic interactions
- Optical Coatings and Gratings
- Cultural Heritage Materials Analysis
- Spectroscopy and Laser Applications
- Ion-surface interactions and analysis
National Research Council Canada
2016-2025
Sensors (United States)
2018
Optica
2018
Nanjing University
2018
University of Kent
2018
Cornell University
2018
ShanghaiTech University
2018
Natural Sciences and Engineering Research Council
2018
Shanghai University
2018
Tianjin University
2018
Linearly polarized femtosecond light pulses, focused inside fused silica to an intensity that leads multiphoton ionization, produce arrayed planes of modified material having their normal parallel the laser polarization. The are < or = 10 nm thick and spaced at approximately lambda/2 in medium for free space wavelengths both 800 400 nm. By slowly scanning sample under a fixed focus, order is maintained over macroscopic distances all angles between polarization scan direction. With direction...
We utilize the interaction of tightly focused ultrashort pulses with transparent media to imprint their local polarization in focal region. In particular, we demonstrate that this technique allows for a subwavelength resolution diagnostic complex states including presence longitudinal component electric field. Moreover, first ever material ablation field femtosecond pulses.
We fabricate microchannels in fused silica by femtosecond laser irradiation followed etching diluted hydrofluoric acid. show a dramatic dependence of the etch rate on polarization, spanning 2 orders magnitude. establish existence an energy-per-pulse threshold at which laser-modified zones becomes highly polarization selective. The enhanced selective is due to long-range, periodic, polarization-dependent nanostructures formed material.
Femtosecond laser radiation tightly focused in bulk fused silica is used to generate self-ordered nanogratings when the sample translated under lens at constant speed. The are preserved over a length scale of millimeters. We demonstrate that formed for all pulse durations tested, ranging from 40to500fs, and energy threshold this phenomenon increases with decreasing duration. use high spatial resolution diagnostics based upon selective chemical etching followed by atomic force microscopy...
We present a comprehensive study on femtosecond laser-induced refractive index modification in wide variety of multicomponent glasses grouped as borosilicate, aluminum–silicate, and heavy-metal oxide along with lanthanum–borate sodium–phosphate glasses. By using high-spatial resolution profiling techniques, we demonstrate that under range writing conditions the can be positive, negative, or nonuniform, exhibits strong dependence glass composition. With exception some aluminum–silicate all...
We demonstrate that micron-sized light-absorbing particles can be trapped and transported photophoretically in air using an optical bottle formed inside the focal volume of a lens with controlled amount spherical aberration. This fiber-based single beam trap used numerous applications where true 3D manipulation delivery airborne micro-objects is required.
We demonstrate experimentally that, in a tight focusing geometry, circularly polarized femtosecond laser vortex pulses ablate material differently depending on the handedness of light. This effect offers an additional degree freedom to control shape and size laser-machined structures subwavelength scale.
We employ conical refraction of light in a biaxial crystal to create an optical bottle for trapping and manipulation particles.We show that by just varying the polarization input can be opened closed at will.We experimentally demonstrate stable photophoretic controllable loading unloading absorbing particles trap.ocis: (350.
Plane-by-plane fabrication of fiber Bragg gratings in optical fibers using a short-pulse femtosecond IR laser is proposed and demonstrated.By incorporating cylindrical lens the setup, plane index modification can be directly inscribed core by single pulse.The planes are produced free-standing without an oil immersion objective.This plane-by-plane method simplifies direct grating inscription process allows for complicated structures.
This paper reports the testing results of radiation resistant fiber Bragg grating (FBG) in random air-line (RAL) fibers comparison with FBGs other radiation-hardened fibers.FBGs RAL were fabricated by 80 fs ultrafast laser pulse using a phase mask approach.The gratings tests carried out core region 6 MW MIT research reactor (MITR) at steady temperature above 600°C and an average fast neutron (>1 MeV) flux >1.2 × 10 14 n/cm 2 /s.Fifty five-day FBG sensors showed less than 5 dB reduction peak...
An ultrahigh-resolution (20nm) technique of selective chemical etching and atomic force microscopy has been used to study the photoinduced modification in fused silica produced at various depths by tightly focused femtosecond laser radiation affected spherical aberration. We demonstrate that shapes irradiated zones near threshold for can be predicted taking proper account aberration caused refractive index mismatched air–silica interface. establish a depth dependence pulse energy required...
We identify two states of stress induced in waveguides fabricated by femtosecond lasers fused silica and show how they can be relieved annealing. In-plane concentration are revealed through birefringence loss measurements. Another kind laser-induced appears the form swelling glass surface when written near is a manifestation confined rapid material quenching. By annealing sample we reduce losses approximately 30% (at 633 nm) decrease factor 4 silica.
We demonstrate a shot-to-shot reduction in the threshold laser intensity for ionization of bulk glasses illuminated by intense femtosecond pulses. For ${\mathrm{SiO}}_{2}$ change serves as positive feedback reenforcing process that produced it. This constitutes memory nonlinear material. The saturates with number pulses incident at given spot. Irrespective pulse energy, magnitude saturated is constant ($\ensuremath{\sim}20%$). However, shots required to reach saturation does depend on...
Tightly focused, linearly polarized, femtosecond laser radiation can produce highly birefringent nanograting structures inside fused silica glass. Here we report that when the polarization direction of light is changed, old nanogratings are erased and simultaneously replaced with new ones whose orientation solely determined by rewrite beam. We also show these volume be rewritten 1000 times little degradation in their quality.
We describe an optical beam converter for efficient transformation of Gaussian femtosecond laser beams to single- or double-charge vortex beams. The device achieves a conversion efficiency 75% and 50% can operate with high-energy broad bandwidth pulses. also show that the topological charge be determined by analyzing its intensity distribution in focal area cylindrical lens.
We demonstrate, both analytically and experimentally, that a broad class of vector bottle beams can be synthesized by passing Gaussian beam through uniaxial c-cut crystal. The polarization state shape the optical easily reconfigured tuning input crystal parameters.
In this article we compare the results of micromachining fused silica and silicon with tightly focused scalar (viz., circularly linearly polarized) vector azimuthally radially femtosecond laser pulses. We show that drilling polarized pulses produces holes smoother better-delineated walls compared other polarizations used, whereas can machine 20-nm wide single grooves in when electric field pulse is aligned perpendicular to cutting direction. The observed polarization-controlled due formation...
New forms of electron beams have been intensively investigated recently, including vortex carrying orbital angular momentum, as well Airy propagating along a parabolic trajectory. Their traits may be harnessed for applications in materials science, microscopy, and interferometry, so it is important to measure their properties with ease. Here, we show how one immediately quantify these beams' parameters without need additional fabrication or nonstandard microscopic tools. Our experimental...
Periodic planar nanostructures are found in Type II-IR Bragg gratings produced SMF-28 fiber by side-illuminating it with infrared femtosecond-laser pulses through a phase mask. The aligned perpendicular to the laser polarization, as demonstrated using scanning electron microscopy analysis of cleaved samples. Dark field optical is employed for real-time monitoring structural changes occurring inside during inscription process.