Slide 1Slide 2Principal components & how lasers workSlide 4Slide 5Some of numerous applicationsMoving Matter with Light without touching ???Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Shaping matter by infrared laser beamsSlide 17Slide 181. Lasers:•What they are & how they work;•Laser tweezers: moving things with light without touching;•Laser applications: science, technology, & everyday life;2. Invisibility:•Is this possible? Yes!!!•How it works & when we can buy our invisibility clothes?3. Energy from light:•Solar cells & solar cell paints;4. Holography & Diffraction GratingsMovie on Optical Science & TechnologyFlashlightLightbulbLaserLightbulbFlashlightLaserRays: Waves:Principal components & how lasers work1. Gain medium2. Laser pumping energy3. Mirror (100% reflection)4. Output coupler mirror (98-99% reflection);5. Laser beam•The term “LASER" is an acronym for Light Amplification by Stimulated Emission of Radiation.•Laser light is spatially coherent: either emitted in a narrow, low-divergence beam, or can be converted into one with the help of lenses. •Lasers are emitting light with a narrow monochromatic wavelength spectrum.Laser in a research lab:Intensity-distribution curve of light from a White fluorescent tubeIntensity-distribution curve of light from a incandescent lamp Compare different light sources:LaserSome of numerous applications•In CD, Blue-Ray, DVD, andHD-DVD players,•Bar code readers;•Laser pointers & laser tweezers;•welding metal and other materials;•"marking"—producing visible patterns such as letters;•Military applications: range-finding, target designation, and illumination, weapons;•Medicine: laser surgery (i,.e., correction of cornea in the eye), diagnostics, and therapeutic applications; •Holography;•Laser microscopy;Moving Matter with Light without touching ???To explain why tails of comets always point away from the Sun, Kepler suggested that the Sun was exerting a sort of radiant pressure. This led him in 1609 to propose sailing from the Earth to the Moon on light itself. This was and still is the stuff of science fiction. Johannes KeplerMoving and shaping matter with light400 years later Kepler's ideas about moving matter with light are a reality(manipulated with invisible infrared light)9Moving and shaping matter with light400 years later Kepler's ideas about moving matter with light are a reality(manipulated with invisible infrared light)10A highly simplified view on How “Optical Trapping” WorksAlong beam axis:Laser beam Refraction changes light (photons) propagation direction; In return, the particle experiences an opposite force; Need refractive index of object > than that of medium;Optical forces for micron-sized objects: In the lateral plane:cPowerF ~ rlaser powefor mW of pN pNFgravity310~11Equivalent ways of steering ObjectiveFocal PlanePrismObjectiveMultiple traps: beam steering and shaping using spatial light modulatorsObjective lensFocal planePhase-only SLMImagecan be scanned at(2) Acousto-Optic DeflectorsHz )101.0( MHz )101( k(1) Galvano mirrors can be scanned at12Dynamically-reconfigurable focused laser beams Infrared CW Nd: YAG λ=1064nm co-localized with a HeNe Laser, λ=632.8nmIntensityBeam steering Objective13Manipulation of multiple micron-sized objects Manipulation by CW Nd: YAG (λ=1064nm), visualized by HeNe laser (λ=632.8nm)14Manipulating micron-sized bacteria9x9 arrayLaser power ~ 10mW per trap6x6 arrayBacteria Pseudomonas aeruginosa:Burns, cancer patients, cystic fibrosis patientsPlanktonic cells send quorum sensing molecules/signals to determine if there are enough bacteria to start a biofilmResistant to antibiotics15Particle manipulation with multiple trapsShaping matter by infrared laser beams17Thank you !!!Optically-manipulated micro-string ( using an infrared laser
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