We propose a new method to measure the absolute photon absorption cross section of neutral molecules in a molecular beam. It is independent of our knowledge of the particle beam density, nor does it rely on photo-induced fragmentation or ionization. The method is based on resolving the recoil resulting from photon absorption by means of near-field matter-wave interference, and it thus applies even to very dilute beams with low optical densities. Our discussion includes the possibility of internal state conversion as well as fluorescence. We assess the influence of various experimental uncertainties and show that the measurement of absolute absorption cross sections is conceivable with high precision and using existing technologies.
Attosecond delay metrology beyond the photon coherence time with spectrally resolved Hong-Ou-Mandel interferometry
University of Ottawa（渥太华大学）；National Research Council of Canada（加拿大国家研究委员会）；Joint Centre for Extreme Photonics, National Research Council and University of Ottawa（极端光子学联合中心（加拿大国家研究委员会与渥太华大学））；School of Mathematics and Physics, University of Portsmouth（朴茨茅斯大学数学与物理学院）；Institute of Cosmology and Gravitation, University of Portsmouth（朴茨茅斯大学宇宙学与引力研究所）；Institute for Quantum Studies, Chapman U（查普曼大学量子研究学院）
