Laser-induced electronic bridge for characterization of the $~^{229\rm{m}}\rm{Th} \rightarrow ~^{229\rm{g}}\rm{Th}$ nuclear transition with a tunable optical laser

TL;DR

This paper explores a theoretical method using laser-induced electronic bridge to determine the energy of the $^{229m}$Th nuclear isomer, potentially enabling highly enhanced nuclear decay rates for experimental measurement.

Contribution

It introduces a new theoretical approach for nuclear energy determination via laser-induced electronic bridge, with detailed rate calculations and experimental considerations.

Findings

Potential for up to 10^8 enhancement in decay rate

Feasibility of using optical/UV lasers for nuclear state detection

Identification of experimental parameters for implementation

Abstract

An alternative method to determine the excitation energy of the $~^{229\rm{m}}\rm{Th}$ isomer via the laser-induced electronic bridge is investigated theoretically. In the presence of an optical or ultra-violet laser at energies that fulfill a two-photon resonance condition, the excited nuclear state can decay by transfering its energy to the electronic shell. A bound electron is then promoted to an excited state by absorption of a laser photon and simultaneous de-excitation of the nucleus. We present calculated rates for the laser-induced electronic bridge process and discuss the experimental requirements for the corresponding setup. Our results show that depending on the actual value of the nuclear transition energy, the rate can be very high, with an enhancement factor compared to the radiative nuclear decay of up to $10^8$.