We report Raman spectra measurements on a MoS2 monolayer supported on SiO2 as a function of temperature. Unlike in previous studies, the positions of the two main Raman modes, 2 1 and 1 exhibited nonlinear temperature dependence. Temperature dependence of phonon shifts and widths is explained by optical phonon decay process into two acoustic phonons. Based on Raman measurements local temperature change under laser heating power at different global temperatures is derived. Obtained results contribute to our understanding of the thermal properties of twodimensional atomic crystals and can help to solve the problem of heat dissipation, which is crucial for use in the next generation of nanoelectronic devices.

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Generation of coherent light with desirable amplitude and phase profiles throughout the optical spectrum is a key issue in optical technologies. Nonlinear wavefront shaping offers an exceptional way to achieve this goal by converting an incident light beam into the beam (or beams) of different frequency with spatially modulated amplitude and phase. The realization of such frequency conversion and shaping processes critically depends on the matching of phase velocities of interacting waves, for which nonlinear photonic crystals (NPCs) with spatially modulated quadratic nonlinearity have shown great potential. Here, we present the first experimental demonstration of nonlinear wavefront shaping with three-dimensional (3D) NPCs formed by ultrafast-light-induced ferroelectric domain inversion approach. Compared with those previously used low-dimensional structures, 3D NPCs provide all spatial degrees of freedom for the compensation of phase mismatch in nonlinear interactions and thereby constitute an unprecedented system for the generation and control of coherent light at new frequencies.

This paper reports novel photoresponsive, processable poly(esterimide)s functionalized with the azobenzene and tricyanovinylene groups. Post and prepolymerization strategies were utilized for preparation of the new photochromic polymers with imide rings. The postpolymerization method of azopolymer synthesis included a functionalization of precursor poly(esterimide) containing dialkylaminophenyl groups with diazonium salt of aniline. The precursor poly(esterimide) was obtained from synthe-

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