Holotrap

Interactive Java application to generate dynamic holographic traps by clicking and dragging the mouse:

Instructions:

  • Press Init before generating any trap. The program reads the file  “defaultProperties.properties”, where you specify:
    1. Phase map file: for example, “map_ideal.txt” (linear phase)
    2. Aberration correction file: for example, “no_ab_400x300.txt” (all zeros, no aberration) or “aberr_hamam_400x300.txt”
    3. Horizontal left position of the hologram: 0 will display the hologram on the left corner of your screen, if you want to display the hologram on the SLM you should chose 800 (the number of pixels of your first display) instead.

 -   All the files have to be in the folder of the program.

-   Note that the aberration file is only 400x300 instead of 800x600. This is because the program computes 400x300 holograms and then repeats the pixels twice, in order to speed up the computation. You need to generate a similar aberration file from your deformation correction pattern.

-   You do also need to generate a phase map (two columns: first column is the phase, from 0 to 6.283, while the second column is the corresponding grey level).

  •  Row factor and Col factor are scaling factors in the vertical and horizontal directions, respectively. They depend on the experimental setup, the hologram is scaled accordingly.
  •  You can generate/delete traps or vortices by clicking the mouse, move them and defocus them (trap depth, arbitrary units). For multiple traps, you can chose the “random mask” algorithm or the “lenses and gratings” one.
  •  Note that the values are only refreshed when you drag the mouse.
  •  Fps: the program indicates the computation rate (frames per second).
  •  This version of the program is compiled with no camera, so you do not see the actual traps or the sample on your screen, together with the circles indicating the centre of the traps or vortices.

More information:

E. Pleguezuelos, A. Carnicer, J. Andilla, E. Martín-Badosa, and M. Montes-Usategui, “HoloTrap: Interactive hologram design for multiple dynamic optical trapping," Comp. Phys. Commun. 176, 701-709 (2007).