08 February 2008 ICFO in OPN

OPN After Image

Roser Juanola and Gabriel Molina’s research is the After Image of OPN current issue. A high definition reconstruction of the amplitude and phase of a complex light beam has been selected as the After Image of Optics & Photonics News (OPN) current issue. The image was produced by Roser Juanola and Gabriel Molina, of the Quantum information with photons group, led by Juan P. Torres.

While the amplitude of a light beam can be easily cached by the eye, the phase is usually invisible. Still, the latter contains much important information, namely temporal data related to the generation time of the beam, the matter it has passed through etc. The image was obtained with a slight modification of a new technique called spiral phase contrast interferometry, which allows one to retrieve both the phase and amplitude of an optical beam with a self-referenced method. The optical Gaussian beam was generated with four optical vortices embedded on it by means of a custom made hologram.

Optical vortices (also known as optical tornadoes or phase singularities) appear as spots where the amplitude of the field vanishes and the phase twists. They have applications in many areas of photonic science, like optical manipulation of matter or optical communications.