Lens-free heterodyne transient grating method for dynamics measurement of photoexcited species in liquid

A recently developed lens-free heterodyne transient grating method was applied for the measurement of ultrafast photoexcited dynamics of several kinds of dye molecules in aqueous solutions. The principle of the lens-free heterodyne transient grating method was clarified in detail, especially for thick samples, such as liquid and semi-transparent solid samples. The ultrafast dynamics of malachite green and methyl orange molecules in aqueous solutions was successfully monitored, and the obtained time constants agreed with those in other reports.