Two-photon exposure of photographic film

Photographic film has commonly been exposed by a single-photon absorption m echanism. We determine the conditions for film exposure by direct two-photo n absorption. Using subpicosecond laser pulses, we find that two-photon exp osure for commercial film has a threshold fluence and an intensity of 0.000 8 J/cm(2) and 0.0066 TW/cm(2), respectively, well below the optical damage threshold. Multiphoton photography has the potential for higher spatial res olution and affords an opportunity for three-dimensional image storage. (C) 1999 Optical Society of America [S0740-3224(99)00304-5] OCIS codes: 190.41 80, 110.5200.