Recently we demonstrated non-contact excitation of broadband mechanical waves in soft media for transient elastography. Using US from an air-coupled transducer focused on an air/medium interface, this method (called 'acoustic micro-tapping', or AμT) provides sufficient radiation force to launch a transient displacement. Combined with ultrafast phase sensitive OCT, AμT-OCT can track propagating mechanical waves with a fully non-contact system appropriate for many applications. Complementary methods are now needed to properly reconstruct the elastic modulus from imaged wavefields. Here we explore the different modes launched by an AμT source that can be tracked efficiently with OCT. The motivation is an optimal method to reconstruct the elastic modulus from complex displacement fields given the highly dispersive nature of waves in bounded media such as the cornea.