Optical bistabilities of higher harmonics: Inhomogeneous and transverse effects

► Optical bistability in two-level system studied outside the rotating wave approximation. ► Transverse field variations and inhomogeneous broadening included. ► Analytical/numerical results obtained with transverse field variation. ► Analytical/numerical results obtained with Lorentzian/Gaussian line profiles. ► First harmonic output field beyond RWA exhibits butterfly OB or reversed OB behavior.