TIME-RESOLVED ULTRANARROW OPTICAL HOLE-BURNING OF A CRYSTALLINE SOLID- Y2O3EU3+

Optical hole burning is used to study optical dephasing of the F-7(0) double-line arrow pointing right 5D0 transition in samples of Y2O3:Eu3 + grown by both flame fusion and laser-heated pedestal growth. The sam ples exhibited a wide variation in their low-temperature hole widths, and the measured hole linewidths were in reasonable agreement with hom ogeneous linewidths obtained from values of T2 that were determined wi th two-pulse photon echoes. The sample that had the longest value of T 2 (510 mus) from the echo measurements gave a hole width of 3.5 kHz. T his is believed to be the narrowest spectral feature observed directly in the frequency domain for a solid. Other samples produced wider hol es that were not correlated with the Eu3+ impurity concentrations. Tim e-resolved hole burning in one of the samples showed a slow and contin uous broadening of the spectral hole from 130 kHz at 3 ms to 900 kHz a t 10 s after hole burning. It is suggested that the additional broaden ing is associated with some form of disorder modes in this ordered cry stalline solid.