The probe absorption characteristic of a four-level ladder-type system, in presence of two strong coherent radiation fields, is investigated analytically by following the density operator method. The parameters of 85Rb 5S1/2→5P3/2→5D5/2→63P3/2 transition are used in the simulation. In addition to the control field acting between the first excited state and the second excited state, if a switching field is applied to couple the second excited state to a Rydberg state, two-photon electromagnetically induced transparency (EIT) is converted into double EIT (DEIT) window having a strong central absorption peak. In a thermal vapor, the double EIT window is transformed into three transparency windows depending on the values of the control and switching Rabi frequencies. These multiple transparency windows vanish for certain combinations of the Rabi frequencies of the control and switching fields and the probe absorption is enhanced. It is also demonstrated how a very narrow optical band stop filter can be conceptualized by using three-photon excitation scheme. The transient optical response of the medium under three-photon transition is also investigated under both Doppler free and Doppler broadened conditions.