Holographic imaging offers a reliable and fast method to capture the complete 3-D information of the scene from a single perspective. We review our recently proposed single-channel optical system for generating digital Fresnel holograms of 3-D real-existing objects illuminated by incoherent light. In this motionless holographic technique, light is reflected, or emitted, from a 3-D object, propa...

BACKGROUND Photodynamic therapy (PDT) with 5-aminolaevulinic acid (ALA) is an effective and safe treatment option for the treatment of actinic keratosis (AK). Incoherent lamps are often used, matching the absorption maxima of ALA. OBJECTIVES A comparative trial was performed to evaluate the efficacy of recently developed light-emitting diodes (LEDs). METHODS Human epidermal keratinocytes we...

We study, theoretically and experimentally, the evolution of optical waves with randomly-fluctuating phases in a spatially chirped nonlinear directional coupler. As the system crosses its linear resonance, we observe collective self-phase-locking (autoresonance) of all mutually-incoherent waves, each with its own pump, and simultaneous amplification until the pumps are exhausted. We show that t...

In this review, we describe our method for creating holograms of incoherent objects, dubbed Fresnel incoherent correlation holography (FINCH). FINCH creates holograms by a single-channel on-axis incoherent interferometer process. Like any Fresnel hologram, the object is correlated with quadratic phase functions, but the correlation is carried out without any movement. Generally, in the FINCH sy...

Incoherent solitons are partially coherent optical beams propagating without changing their shape in materials with a slow nonlinear response [1, 2]. Such nonlinear materials respond to the time averaged light intensity, which means that even though the phase of the partially coherent light beam fluctuates randomly, it still leads to a smooth light-induced refractive index change and subsequent...

We study the propagation dynamics of an incoherent light beam circulating in a passive cavity containing noninstantaneous nonlinear media. It is shown that patterns form in this cavity in spite of spatial incoherence of the light. We show that the pattern formation process is always associated with two consecutive thresholds. The first (instability) threshold is unaffected by the cavity boundar...

We report on efficient coherent addition of spatially incoherent multimode laser beam distributions. Such addition is demonstrated within a multi-channel laser resonator configuration, obtaining more than 90% combining efficiency while preserving the good beam quality. We explain the rather surprising physical phenomenon of coherently adding spatially incoherent light by self-phase-locking of e...

Incoherent subharmonic light scattering in isotropic media is a new kind of nonlinear light scattering, which involves single input photon and multiple output photons of equal frequency. We investigate theoretically the dependence of the subharmonic scattering intensity on the hyperpolarizability of molecules and the incident intensity using nonlinear optics theory similar to that used for Hype...