Optical tweezers

1,228 views
804 views

Published on

This presentation is all on optical tweezers .Optical tweezers (originally called "single-beam gradient force trap") are scientific instruments that use a highly focused laser beam.

Published in: Education, Technology, Business
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
1,228
On SlideShare
0
From Embeds
0
Number of Embeds
6
Actions
Shares
0
Downloads
41
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Optical tweezers

  1. 1. OPTICAL TWEEZERS: THE FORCE OF LIGHT
  2. 2. Introduction General description Working Vedio of traping particle Diagrams of instrument Application
  3. 3. INTRODUCTION Optical tweezers: Light can exert forces on small dielectric objects1, A tightly focused beam of light can trap micron-sized objects, such as latex beads. This “optical trapping” principle has found many applications in chemistry, physics and biology. It has found its most prominent use in
  4. 4. OPTICAL TWEEZERS ? An optical tweezer is a scientific instrument that uses a focused laser beam to provide an attractive or repulsive force, depending on the index mismatch (typically on the order of piconewtons) to physically hold and move microscopic dielectric objects. Optical tweezers have been particularly successful in studying a variety of biological systems in recent years. Dielectric objects are attracted to the center of the beam, slightly above the beam waist, as described in the text. The force applied on the object depends linearly on its displacement from the trap center
  5. 5. Trapping a particle with light 5
  6. 6. Optical Tweezers rolf 6
  7. 7. WORKING OF TWEEZER YouTube - Protein crystal in optical tweezers.flv
  8. 8. WORKING The Nd:YAG laser (1064 nm wavelength) is the most common laser choice because biological specimens are most transparent to laser wavelengths around 1000 nm. This assures as low an absorption coefficient as possible, minimizing damage to the specimen, sometimes referred to as opticution. Perhaps the most important consideration in optical tweezer design is the choice of the objective.
  9. 9. Basic Components Laser L1 L2 f1 + f2 L3 Objective Lens f3 16 cm Image created from Physlet at http://webphysics.davidson.edu/Course_Material/Py230L/optics/lenses.htm Physlet by Dr. Wolfgang Christian and Mike Lee
  10. 10. Schematic diagram Laser line mirror Laser Beam expander Cell White Light Source CCD Color Filter Laser line mirror Objective Tip 12
  11. 11. Dual beam tweezer design 13
  12. 12. Kinesin motor motion RAY OPTICS RADIATION PATTERN •A laser beam is expanded and collimated. This collimated beam is directed through a microscope objective into a flow cell. Spheres with a higher index of refraction than the medium in the cell (water) will be trapped at the focus of the beam.
  13. 13. YouTube - real-life Tetris under a microscope.flv
  14. 14. APPLICATIONS We will calibrate the strength of an optical trap (Optical Tweezer) Optical Tweezers may be used to measure very small forces (femtoNewton, 10-15N) Applications include Biophysics 16
  15. 15. k YOU FOR YOUR ATTENTIO N

×