The stated invention proposes an apparatus and technique for quick  sterilization of substrates and/or medium, especially surgical tools, for elimination of high load of broad range of pathogens. The surgical tool or the pathogen culture to  be sterilized is irradiated with light of certain wavelength in the presence of nanomaterial suspension such as silver/gold nanoplates or combination with gold  nanospheres etc. The invented method involves use of low temperature and atmospheric pressure for the destruction of pathogens within few minutes of complete cycle  leading to sterilization. The photothermal repeatability of the nanoplates suspension upon repeated irradiation as well as sterility is demonstrated for re-use for multiple  number of sterilization cycles. Also, the continuous flow based device is proposed for large scale use. Sterilization efficacy of the proposed invention is demonstrated  through the sterilization of surgical tools as well as for the pathogen cultures leading to 7.69 log10 reductions for each pathogen (complete eradication of the pathogenic  culture), which meets the SAL (Sterility Assurance Limit) norms to be achieved for the combinations of ESKAPE and fungal pathogens.