Basics about spatial coherence:

No interference

From the figures above it can be seen directly, that either the distance from the object to the sensor has to be small or the interference-partners have to be close together to get the required fringes.

Lensless Microscope – New Approach (Version 2)

When building the first version of the Holoscope using but-coupled LEDs, it turned to be really hard putting the fibres in to the right position of the LEDs. The fibres are really thin and the efficiency degrades dramatically if the fibre is not positioned directly on the led’s dye.

Lensless Microscope – New Approach (Version 2)

When building the first version of the Holoscope using but-coupled LEDs, it turned to be really hard putting the fibres in to the right position of the LEDs. The fibres are really thin and the efficiency degrades dramatically if the fibre is not positioned directly on the led’s dye.

Another idea is to use a pico projector which uses a DMD-Display. It’s a micro-mirror device which has a matrix with thousands of small mirrors which can be switched on and off. The ratio of this on/off-thing gives the grayvalue. When illuminating the DMD with the three basic colours red-green-blue sequentially one could mix all possible colours.

The new optical setup shows the illumination-concept. Good side-effect is, that the coherence ratio can be setup depending on the diameter of the aperture. The aperture thus can be scanned of the matrix, which gives the required shift for superresolution.

Different illumination patterns are possible (Line instead of point, etc.). So this system holds some advantages compared to a traditional lightmicroscope. There is no expansive optics needed which could aberrate the image. It’s quiet cheap. In total one spends about 200 Euro for the Webcam + DLP and so.

Due to the Subpixel superresolution one can get high resolution images at a high FOV (field of view) . This system is portable and more-less robust.