The Optomechanical Effect in Amorphous Chalcogenide Films

Polarization-dependent photoinduced mechanical deformations in covalent chalcogenide glasses

“…One is an optomechanical ͑OM͒ effect, 15,[17][18][19][20] which is a polarization-dependent deflection of small bilayer cantilevers consisting of As-S-Se and Si ͑or Si 3 N 4 ͒. A similar phenomenon is reported also for As 50 Se 50 /mica cantilevers by Trunov and Bilanich.…”

“…It is clear from ͑a͒ that the perpendicular polarization produces greater cantilever deflection, which probably arises from elongation of the chalcogenide films along the cantilever axis. However, in ͑a͒ and in all the previous studies, 15,[17][18][19][20][21] it has not been known if the parallel polarization produces real film contractions along the axis, since the polarization-dependent displacement is biased by the greater initial response, i.e., 110 10 m in Fig. 3͑a͒.…”

“…15,[17][18][19][20][21] When linearly polarized illumination is started at 0 min, irrespective of the polarization direction, the cantilever bends as if the chalcogenide film expands ͑⌬ Ϸ 110 m͒, which possibly reflects the isotropic expansion ͓Fig. 1͑a͔͒, a difference of thermal expansions between As 2 S 3 and substrates, 20 and photoinduced stress relaxation.…”

“…4, which is consistent with the previous result. [17][18][19][20] In the case of ͑b͒ Se, relaxation under illumination, known as photoinduced stress-relaxation, 33 is remarkable. But, we see that perpendicular and parallel polarization tend to lengthen and shorten Se films along the cantilever axis, in a similar way to that in ͑a͒ As 2 S 3 .…”

“…The OM effect will be measured in somewhat different ways from those employed previously. 15,[17][18][19][20] …”