Enhanced X-ray emission from nano-particle doped bacteria

Abstract

Recently, it has been greatly appreciated that intense light matter interaction is modified due to the nano- and microstructures in the target by – surface plasmons, laser energy localization scattering etc. Extreme laser intensities produce dense plasmas and collective mechanisms generate energetic electrons, ions and hard X-rays. Recently, it is postulated that the anharmonic electron motion, driven by ultrashort, high-intensity laser pulses, provides a universal mechanism for the laser absorption. Here, we provide the first demonstration of anharmonic-resonance-aided high laser-absorption in a biological system. At intensities of ∼10^16–18 W/cm², 40 fs pulses excite a plasma formed with E. coli bacteria. The density-inhomogeneities due to the micro- and nanostructures in the bacterial target increase Anharmonic Resonance (AHR) heating and result in a 10⁴-fold enhancement in the hard X-ray yield compared to plain solid targets. These observations lead to novel high-energy X-ray sources that have implications to lithography, imaging and medical applications.