EFFECT OF DIFFRACTION ON EARLY-ARRIVING PHOTONS DURING FEMTOSECOND LASER TRANSILLUMINATION OF HIGHLY SCATTERING MEDIA OF BIOLOGICAL SIGNIFICANCE

Early-arriving photons of 100-fs laser pulses transmitted through high ly scattering media have been detected by a streak camera. Because of their partial spatial coherence, they are affected by diffraction from small hidden discontinuities. The experimental data of the patterns a re analyzed with Fresnel diffraction theory and then corrected accordi ngly. Submillimeter hidden objects were scanned and imaged. Diffractio n correction resulted in a significantly improved contrast in the hidd en object's image.