Optical transistor and router application of Autler–Townes-splitting in various solid atomic-like media

We compare the Autler–Townes (AT)-splitting in ${{\rm Eu}^{3 + }}{:}{{\rm YPO}_4}$Eu3+:YPO4, ${{\rm Pr}^{3 + }}{:}{{\rm YPO}_4}$Pr3+:YPO4, and ${{\rm Pr}^{3 + }}{:}{{\rm Y}_2}{{\rm SiO}_5}$Pr3+:Y2SiO5 crystals. The AT-splitting in ${{\rm Pr}^{3 + }}{:}{{\rm Y}_2}{{\rm SiO}_5}$Pr3+:Y2SiO5 is stronger than other two-doped crystals, while the ${{\rm Pr}^{3 + }}$Pr3+ ion has a stronger dressing than the ${{\rm Eu}^{3 + }}$Eu3+ ion in a host material of YPO. The stronger dressing in YSO is attributed to the ${{\rm C}_{2h}}$C2h symmetry of the YSO crystal and its nondegeneracy, making the dressing sensitive to doped material. By investigating the relationship between spectral AT-splitting (SAT-splitting) and temporal AT-splitting (TAT-splitting), we observed that TAT-splitting depends upon the dressing effect and phonon-assisted nonradiative transition whereas SAT-splitting results only from the dressing effect. Based on our results, we proposed a model for an optical router and transistor (amplifier and switch). The router action results from the SAT- and TAT-splitting while the transistor was realized by a switch from bright to dark dressed states.