Femtosecond Circular Photon Drag Effect in the Ag/Pd Nanocomposite

Abstract

We report on the observation of the helicity-dependent photoresponse of the 20-μm-thick silver–palladium (Ag/Pd) nanocomposite films. In the experiment, 120 fs pulses of Ti:S laser induced in the film an electric current perpendicular to the incidence plane. The photoinduced current is a linear function of the incident beam power, and its sign depends on the beam polarization and angle of incidence. In particular, the current is zero for the p- and s-polarized beams, while its sign is opposite for the right- and left-circularly polarized beams. By comparing experimental results with theoretical analysis, we show that the photoresponse of the Ag/Pd nanocomposite originates from the photon drag effect.

Influence of Electrochemical Hydrogenation on the Circular Photocurrent in the Ag/Pd Nanocomposite

“…According to our results, presented in ref. the CPC generated in the investigated Ag/Pd films is consistent with the circular PDE theory. CPGE does not occur in Ag/Pd films, because Ag/Pd films consist of non‐gyrotropic nanocrystallites of Ag‐Pd solid solution and PdO .…”

“…In refs. , we have shown that the photocurrent in Ag/Pd nanocomposite is generated due to PDE and SPGE. This conclusion was based on the obtained angular and polarization dependencies characteristic to PDE and SPGE.…”

“…Upon laser irradiation, a photocurrent was generated in the Ag/Pd film. It should be noted that at a normal incidence of laser radiation on the film ( α = 0), there is no photocurrent . In the experiments, the transverse photocurrent, that is, photocurrent with a direction perpendicular to the plane of incidence σ of laser radiation along the y ‐axis (Figure c), was recorded.…”

“…In previous studies, it was shown that the photocurrent depends linearly on the power of laser irradiation . Therefore, it is reasonable to represent the transverse photocurrent as normalized to the power of the incident laser pulses, that is, in the form of the conversion coefficient η y , defined as η y = j y τ/ E in , where E in is the input laser pulse energy.…”

“…Recently, an active study of the light‐induced current sensitive to the polarization of an exciting laser beam (polarization‐sensitive photocurrent) has been reported . These studies are of fundamental importance for the development of optoelectronics and are of practical interest for development of non‐optical polarization analyzers of laser radiation . One of the most interesting phenomena of the polarization‐sensitive photocurrent is the circular photocurrent (CPC), which is excited by a circularly or elliptically polarized radiation.…”