We present a single-shot detection technique for field-free molecular alignment. The method is based on probing the time-varying birefringence of an aligned sample by use of a chirped probe pulse, thus encoding the dependence of the alignment on time onto the spectral domain. The technique is applied to alignment of O2. The recorded signals are well described by an analytical formula.
View online : Opt. Lett. 30, 2326-2328 (2005)