The observation of the picosecond thermal expansion of an absorbing surface after a short heating pulse is reported for the first time to my knowledge. The measurement was performed on Si by adapting the method of photothermal deflection to a pump–probe technique using 1-psec laser pulses. This was achieved by separating out a novel deflection effect due to the gradient in the near-surface optical constants. The results are compared to a thermo-elastic model, and good agreement is found.
© 1988 Optical Society of America
Original Manuscript: March 30, 1988
Manuscript Accepted: June 6, 1988
Published: September 1, 1988
Joshua E. Rothenberg, "Observation of the transient expansion of heated surfaces by picosecond photothermal deflection spectroscopy," Opt. Lett. 13, 713-715 (1988)