Abstract

Twilight-field method for obtaining interference fringes with higher contrast in in-line digital holography regulates only an intensity of the reference light to be close to one of the object light that is ultra weak scattering light from a nanoparticle using a low-frequency attenuation filter. Coherence of light also strongly relates to the contrast of interference fringes. High coherence makes a lot of undesired coherent noises, therefore the fringes derived from nanoparticles is masked by them. Too low coherence makes fringes with low contrast in small area. Consequently an adequately-controlled coherence gives the best performance in the three-dimension position measurement of gold nanoparticles.

© 2015 Optical Society of America