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Optical Tweezers for Biological Manipulation using Cylindrical Vector Beams. By Yen Chin Woo Advisor Professor James Leger Spring 2004. Summary. Introduction to optical tweezers Development of individual systems White light Imaging Laser construction
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Optical Tweezers for Biological Manipulation using Cylindrical Vector Beams By Yen Chin Woo Advisor Professor James Leger Spring 2004
Summary • Introduction to optical tweezers • Development of individual systems • White light Imaging • Laser construction • Development of the whole system • Backlight Imaging • Combination of Nd:YAG laser and backlight • Budget Optical Tweezers for Biological manipulation using Cylindrical Vector Beams
What are Optical Tweezers? • Tool for manipulating microscopic biological objects, such as cells and bacteria. • For focused light beam, the intensity maximum occurs at the focus, so the particles will be attracted to the focus. • Many areas of applications: • Biology • Genetics • Neuroscience • Molecular Medicine • Pharmacy • Biotechnology • Reproductive Medicine Fig 1. Optical Tweezers Setup in the Lab Optical Tweezers for Biological manipulation using Cylindrical Vector Beams
New Design of Optical Tweezers • Systems: • White light Imaging • Nd:YAG laser • Laser/white light optical system • Polarization system • Tweezers can trap and hold small particles with different refractive indices by changing the beam shape Fig 2. Our Design of Optical Tweezers Optical Tweezers for Biological manipulation using Cylindrical Vector Beams
+ = Radially Polarized Azimuthally Polarized Generalized Cylindrical Vector Beam + = Focus shaping using cylindrical vector beams Intensity distribution at focal spot Example: Centered peak beam or • The linearly superposition of radially polarized and azimuthally polarized components is a generalized cylindrical vector beam. • Different polarization results in different focused spot shape Optical Tweezers for Biological manipulation using Cylindrical Vector Beams
Fiber Illuminator (i) Metal in 3D view (iii) Knife Edge (ii) Knife (i) Metal Testing of White Light Imaging System • White light imaging is used to locate an observed sample • System consists of fiber illuminator, camera, and objective • This optical system will be merged with high power laser Optical Tweezers for Biological manipulation using Cylindrical Vector Beams
Laser design and construction (i) Laser Diagram • Stable if • Choose d = 47 cm • Mode size: (ii) Resonator Stability Diagram Optical Tweezers for Biological manipulation using Cylindrical Vector Beams
Testing of Nd:YAG Laser beam (i) Multiple spatial mode (ii) Tem00 • Multiple mode • Design to ensure fundamental oscillation • Measurements of power (Output coupler mirror: 3 Watts, End mirror: 50 mW) Optical Tweezers for Biological manipulation using Cylindrical Vector Beams
Testing of Imaging Optics • Spheres prepared in water • Spheres imaged with a resolution of better than 0.3um Fig 3. Backlight Imaging Optical Tweezers for Biological manipulation using Cylindrical Vector Beams
Testing of Tweezers • Used the combination of Nd:YAG laser and backlight • Trapping demonstrated • Only linearly polarization used Fig 4. The Whole Optical System Optical Tweezers for Biological manipulation using Cylindrical Vector Beams
Construct Nd:YAG laser and arrange the design of the tweezers. Revision and Finalization Revision and Finalization Revision and Finalization Searching articles And references Searching articles And references Searching articles And references Examine different polarization states Timeline Past Demonstrating Tweezers Construct Nd:YAG Laser and arrange the design of the tweezers Demonstrating Tweezers Examine different polarization states Current Construct Nd:YAG Laser and arrange the design of the tweezers Examine Linear Polarization state Demonstrating Tweezers Optical Tweezers for Biological manipulation using Cylindrical Vector Beams
Past Budget $ 0 Printing and photocopying are covered by HKN and the UMN Electrical Engineering Department $ 200 Polystyrene spheres $ 0 Research resources will be provided by Professor Leger Total : $ 200 Current Budget $ 0 Printing and photocopying are covered by HKN and the UMN Electrical Engineering Department $ 180 Polystyrene spheres $ 120 Microscopic objective Total : $ 300 Budget The estimated costs for the project are listed: Optical Tweezers for Biological manipulation using Cylindrical Vector Beams
Summary • Introduction to optical tweezers • Development of individual systems • White light Imaging • Laser construction • Development of the whole system • Backlight Imaging • Combination of Nd:YAG laser and backlight • Budget Optical Tweezers for Biological manipulation using Cylindrical Vector Beams