Incoherent photon echo in ruby using optical fiber for transportation of exciting pulses

The experimental results of investigation of the incoherent photon echo (IPE) in ruby (with $\text{Cr}^{3+}$ concentration equal to 0.16 wt.%) at $T=1.7$ K are presented. The first exciting laser pulse was directed to the sample by means of optical fiber (diameter — 100 ${\rm \mu}$ and length – 3 m). The dependence of the IPE intensity on the excitation wavelength, which is varied within the width of $R_1$ absorption line, was studied. The IPE decay curve was obtained and the phase relaxation time was determined.