Abstract: A method is provided for selectively inactivating microorganisms with femtosecond pulsed lasers. Under proper laser conditions, irradiation of the femtosecond pulsed laser causes inactivation of pathogenic microorganisms, for example, viruses, bacteria and protozoa, without causing cytotoxicity in mammalian cells. Pathogenic microorganism activity is diminished through an impulsive stimulated Raman scattering process, that is, through the excitation of the low-energy vibrational state on the outer structure of a microorganism with femtosecond pulsed lasers. The wavelength of the laser pulses is in a range of the electromagnetic spectrum, for example, visible and near-infrared where water is substantially transparent. The method is utilized for cleansing blood components, disinfecting drinking water, treating viral and bacterial diseases, extracting nucleic acid from microorganisms, and for manufacturing vaccines.

Abstract: The invention relates to a method of inactivating or diminishing the activity of microorganisms and an apparatus implementing that method. Microorganism activity is diminished through exciting the vibrational state of a microorganism with pulses of radiation femtoseconds in width. The wavelength of the pulses is in a range of the electromagnetic spectrum to which water is substantially transparent such as visible light. The pulses cause the microorganisms to vibrate such that their activities become diminished. A laser produces the pulses. A harmonic generator then acts upon the pulses to produce a scattering effect that is used to irradiate the microorganisms. One such laser is a titanium sapphire laser. One example of a harmonic generator is a nonlinear crystal such as a BBO crystal. The apparatus may also have a focusing lens such as a microscope objective that focuses the beam on a microorganism. The invention is effective for the inactivation of viruses or bacteria.