Resumen
An electromagnetically induced transparency (EIT) of a cascade-three-level atom involving Rydberg level in a room-temperature cell, formed with a cesium 6??1/2
S
1
/
2
-6??3/2
P
3
/
2
-66??1/2
S
1
/
2
scheme, is employed to detect the Autler-Townes (AT) splitting resulted with a 15.21-GHz microwave field coupling the 66??1/2
S
1
/
2
?65??1/2
P
1
/
2
transition. Microwave field induced AT splitting, ??????
f
A
T
, is characterized by the distance of peak-to-peak of an EIT-AT spectrum. The ??????
f
A
T
dependence on the microwave Rabi frequency, O????
O
M
W
, demonstrates two regions, the strong-coupling linear region, ??????
f
A
T
? O????
O
M
W
and the weak-coupling nonlinear region, ??????
f
A
T
?O????
O
M
W
. The ??????
f
A
T
dependencies on the probe and coupling Rabi frequency are also investigated. Using small probe- and coupling-laser, the Rabi frequency is found to enlarge the linear regime and decrease the uncertainty of the microwave field measurements. The measurements agree with the calculations based on a four-level atomic model.