Optical tweezers
View Patent ↗An imaging device using an array of active pixels, with a readout control for outputting from selected regions of interest is disclosed. When used to detect the positions of optically trapped objects, the fast readout rate enables fine control of the optical traps to stabilize the objects. Multiple objects can be controlled while being moved relative to each other.
1. Apparatus comprising:
a trap generator for generating and controlling one or more optical traps in a sample space;
an array of active pixels arranged to detect movement of one or more objects within the sample space; and
a readout control adapted to read one or more selected subsets of the active pixels at a rate of at least 1 kHz.
2. The apparatus of claim 1 further comprising a controller in communication with the readout control and adapted to select the one or more subsets of active pixels.
3. The apparatus of claim 2 wherein the controller is adapted to change the one or more subsets of active pixels in response to the movement of the one or more objects within the sample space.
4. The apparatus of claim 2 wherein the controller is adapted to change the one or more subsets of active pixels in response to changes in the control of the one or more optical traps.
5. The apparatus of claim 2 , wherein the controller is configured to select the one or more subsets of active pixels in the form of predetermined patterns that correspond substantially in shape to cross-sectional profiles of the one or more objects.
6. The apparatus of claim 2 , wherein the controller is configured to select the one or more subsets of active pixels in the form of predetermined patterns that correspond substantially in shape to edge profiles of the one or more objects.
7. The apparatus of claim 2 , wherein the controller is additionally in communication with the trap generator, and wherein the controller is adapted to analyse the position of the optical traps and the data read by the readout control so as to generate correctional adjustments to the trap generator.
8. The apparatus of claim 7 , wherein the controller is adapted to provide feedback control data to the trap generator.
9. The apparatus of claim 1 adapted to hold the one or more objects within the one or more optical traps.
10. The apparatus of claim 1 , wherein the readout control is adapted to read the one or more selected subsets of the active pixels at a rate of at least 10 kHz.
11. The apparatus of claim 1 , further comprising a light source for illuminating the one or more objects and an image sensor for collecting illuminating light scattered by the one or more objects.
12. The apparatus of claim 1 , wherein the trap generator comprises a laser source and one or more optical elements for focussing light from the laser source to generate the one or more optical traps.
13. A method of imaging one or more objects comprising the steps of:
generating one or more optical traps in a sample space;
optically trapping the one or more objects to be imaged within the one or more optical traps;
collecting light scattered or emitted by the one or more objects with an array of active pixels;
selecting a subset of active pixels;
addressing the selected subset of active pixels; and
repeating the addressing of a selected subset of active pixels at a rate of at least 1 kHz.
14. The method of claim 13 wherein the repeat addressing is at a rate of at least 10 kHz.
15. The method of claim 13 , wherein the selected subset of active pixels form patterns that correspond substantially in shape to cross-sectional profiles of the one or more objects.
16. The method of claim 13 , where the selected subset of active pixels forms patterns that correspond substantially in shape to edge profiles of the one or more objects.
17. The method of claim 13 , wherein the selected subset of active pixels that are addressed changes for subsequent addressing cycles to form changing patterns.
18. The method of claim 13 , further comprising the step of illuminating the one or more objects such that the array of active pixels collects illuminating light scattered by the one or more objects.
19. The method of claim 13 , further comprising the step of repositioning one or more of the one or more optical traps.
20. The method of claim 19 , wherein the collected light data is used in the repositioning of the one or more optical traps.
21. The method of claim 13 , further comprising the step of analysing the position of the one or more optical traps and the collected light data to provide positional data of the one or more objects held within the one or more optical traps.