Laser‐Induced Reversible Deformation of Europium Stark Levels in Fluorite

Abstract

An effect has been revealed associated with the l a s e r field action, which can be conventionally called Stark level reversible deformation and which was observed in the one-photon luminescence excitation (OPLE) spectrum of the europium transition 7F0+5G2 in fluorite. Its essence lies in such reversible OPLE spectrum changes as component frequency displacement, component relative intensity redistribution and integrated intensity reduction of the spectrum by a factor not l e s s than 2.5.The effect was revealed during two-photon luminescence excitation (TPLE)investigations under conditions described in /I/. In addition, it is noteworthy that the recorded luminescence of the 5D0-47F1 transition was selected by a grating monochromator with a slit spectral width of 2 0 nm. Thus, the total transition luminescence was recorded. The excitation and observation conditions of the OPLE spectrum are schematically shown in Fig. 1. The small circle (shaded) with the a r e a S1 corresponds to the cross-section of the sample region which was laser-field effected by a pulse series with a mean peak intensity per series of about 50 MW cm'2 The large circle with the a r e a S2 corresponds to the cross-section of the