Modified Gabor inline holographic system

From previous results, it could be seen that the Gabor inline system could magically reconstruct the image of the sample without any lenses. The resolution of Gabor inline system, however, reaches only 2.76 µm with 5 µm pinhole. In order to improve the resolution, we designed modified Gabor inline holographic system by adding a microscope objective (MO). The advantages of this system are as follows.

• The microscope objective provides a large magnification factor;

• The microscope objective increases the resolution of the system;

• Larger pinhole could be used as the filter of the light source.

System setup

(a) (b)

Figure 1. (a) System diagram and (b) experimental setup of the modified Gabor inline system

Fig. 1 illustrates the diagram and setup of the modified Gabor inline system, which is basically the same with original Gabor inline system except for a microscope objective. The microscope objective was placed right behind the sample in order to collect the diffraction light from the sample. The microscope objective enlarges the diffraction pattern and casts it on the imaging sensor.

Experimental result

(a) (b)

Figure 2. (a) Hologram and (b) reconstructed image of the modified Gabor inline system

As the basic principles of modified Gabor inline system are the same with Gabor inline system, the reconstruction algorithms of Gabor inline system are also appropriate for the modified one. Fig. 2 shows the experimental results of the modified system. Apparently, the magnification of this system is much larger than that of previous system. And the resolution is significantly improved and even the smallest elements of group 7 (width: 2.2µm) are clearly resolved.