Multiphoton absorption in optical gratings for matter waves

Abstract

We present a theory for the diffraction of large molecules or nanoparticles at a standing light wave. Such particles can act as a genuine photon absorbers due to their numerous internal degrees of freedom effecting fast internal energy conversion. Our theory incorporates the interplay of three light-induced properties: the coherent phase modulation due to the dipole interaction, a non-unitary absorption-induced amplitude modulation described as a generalized measurement, and a coherent recoil splitting that resembles a quantum random walk in steps of the photon momentum. We discuss how these effects show up in near-field and far-field interference schemes, and we confirm our effective description by a dynamic evaluation of the grating interaction, which accounts for the internal states.

Matter-wave physics with nanoparticles and biomolecules

“…Fluorescence or phosphorescence are not entirely excluded for all molecules, and might localize the molecule to half of the wavelength of the emitted radiation. This has been taken into account in a recent theoretical model, too [68].…”

Isotope-selective high-order interferometry with large organic molecules in free fall

“…Three such gratings arranged in space and time form OTIMA, which has already been used to study the matter-wave nature of cold van der Waals clusters [11]. Measurement-induced beam splitting can also be extended to two-photon-ionization [31] or photofragmentation [32]. Photo-depletion gratings can address a large variety of particles in the same setting and are interesting for testing the quantum superposition principle in new complexity regimes [33] or for exploring new avenues in molecular spectroscopy [34].…”