Reference-free wave-front sensor based on the Talbot effect

Wavefront sensing techniques with local slopes measurement (the Shack-Hartmann sensor or the similar one based on the Talbot effect) involve a reference wave, which is supposed to be of well-known shape (plane or spherical). But sometimes the reference wave can’t be formed easily, for example, in X-ray measurements. A reference-free wavefront reconstruction based on the Talbot sensor is discussed in the paper. The spot images are formed in several sequential planes due to the Talbot effect. It allows reconstruct the wave front from two object images in nearby planes without a reference. The self-reproduction phenomenon takes place in a wide wavelength range, so field of use of the Talbot sensor can be significantly expanded. Experimental results of the reference-free reconstruction of a 2nd order aberration of optical wave have been compared with the classical approaches for the Shack-Hartmann and Talbot sensors.