Phase difference enhancement with classical intensity interferometry

• A method of phase difference enhancement is proposed.
• It is based on the classical intensity correlation.
• It serves to increase sensitivity and accuracy in interferometric measurements.
• It can be readily implemented in practice in comparison with all other methods.
• A novel function of classical intensity interferometry is established.

It is demonstrated theoretically and experimentally that, as a novel function of classical intensity interferometry, a phase difference distribution recorded in the form of an interferogram can be enhanced by a factor of 2 on the basis of the classical intensity correlation. Such phase difference enhancement which is also referred to as phase difference amplification is, in general, known to be practically important since it increases sensitivity and accuracy in interferometric measurements. The method proposed in this study prevails over the existing methods in the sense that it can be readily implemented without difficulty in comparison with all other methods so far proposed, although the phase difference enhancement is limited to a factor of 2 in our method and thus so is the improvement of sensitivity and accuracy.