Observation and Control of Laser-Enabled Auger Decay

Abstract

Single photon laser enabled Auger decay (spLEAD) has been redicted theoretically [Phys. Rev. Lett. 111, 083004 (2013)] and here we report its first experimental observation in neon. Using coherent, bichromatic free-electron laser pulses, we have detected the process and coherently controlled the angular distribution of the emitted electrons by varying the phase difference between the two laser fields. Since spLEAD is highly sensitive to electron correlation, this is a promising method for probing both correlation and ultrafast hole migration in more complex systems.

A detailed investigation of single-photon laser enabled Auger decay in neon

“…The angular asymmetries were calculated by equation (2); in the case of bichromatic light their variation was measured as a function of phase and fitted by equation (3). Bichromatic light at frequencies ω and 2ω was generated, and the relative phase scanned, as described in [4,11]. The pulse durations of ω and 2ω were calculated to be 40±12 fs and 30±8 fs, respectively; the relative spectral bandwidth, as measured with the online spectrometer available at FERMI [12] was 1.5×10 −3 .…”

“…De-excitation processes have been studied since the early part of the 20th century, so it is surprising that some have only been predicted and observed recently. An example of a recent discovery is single-photon laser enabled Auger decay (spLEAD) [3,4]. In this process, an excited atomic or molecular ion that does not contain sufficient internal energy to decay by an Auger process is immersed in a laser field, and can obtain the missing energy by absorption of a photon from the field.…”

“…In this paper we report a detailed investigation of spLEAD in neon atoms, which we first reported in [4], using monochromatic or phase-locked bichromatic laser light. The latter is not a prerequisite for spLEAD to occur, but in the simpler case of monochromatic light it is often difficult to distinguish spLEAD from other processes, such as two-photon ionisation of an ion.…”

“…The latter is not a prerequisite for spLEAD to occur, but in the simpler case of monochromatic light it is often difficult to distinguish spLEAD from other processes, such as two-photon ionisation of an ion. It has been shown that by using phase-locked bichromatic light, interference conditions can be created such that the same final state is reached by two quantum paths [4], one of which is spLEAD. The observation of the interference then proves that the process is active, and so our experimental method provides a window for observing spLEAD.…”

Resonant Interatomic Auger Transition in Chalcopyrite CuInSe2

“…ICD can serve as the main mechanism for rapid deexcitation of hollow atoms arising from the neutralization of a highly charged ion in solids . Recently, the single‐photon laser‐enabled Auger decay in Ne atoms decay was experimentally detected . Most of the investigations was aimed at the study of atomic transitions involving valence electrons.…”