Ultrahigh resolution spectroscopy based on photon echo

H. Harde, H. Burggraf

Vitali V. Samartsev

R. M. Macfarlane, Robert M. Shelby, R. L. Shoemaker

R. M. Macfarlane, Robert M. Shelby, R. L. Shoemaker

By using a new, delayed-heterodyne photon-echo technique, we have obtained a spectral resolving power of 1.2\ifmmode\times\else\texttimes\fi{}${10}^{11}$, measuring a 2.0-kHz linewidth (half width at half maximum) for the 6105-\AA{} $^{1}D_{2}\ensuremath{\leftrightarrow}^{3}H_{4}$ transition of YAl${\mathrm{O}}_{3}$: ${\mathrm{Pr}}^{3+}$ in an external magnetic field. This appears to be the highest resolution ever obtained in optical spectroscopy. Measurements were also made on the corresponding transition of La${\mathrm{F}}_{3}$: ${\mathrm{Pr}}^{3+}$ giving a linewidth of 5 kHz. Optical free induction decay gave incorrect results (i.e., significantly broader linewidths).

Y. P. Wang, Richard S. Meltzer

We describe and demonstrate a method for performing ultrahigh-resolution optical spectroscopy in the time domain which utilizes modulations in the intensity of the two-pulse photon echo in the presence of a perturbation that splits the optical transition frequencies of two or more subgroups of ions. The method is applied to a measurement of the pseudo-Stark effect in alexandrite and ${\mathrm{YAlO}}_{3}$:${\mathrm{Er}}^{3+}$. Stark shifts of \ensuremath{\simeq}100 kHz are observed, but the technique is capable of resolutions 10 kHz in some systems.