Pyroelectric and nonlinear optical properties of poled polyvinylidene fluoride films

Oriented films of polyvinylidene fluoride [(CH2CF2)n] can be made significantly pyroelectric and optically nonlinear by poling in a field ∼ 106 volt/cm. Pyroelectric coefficients as large as 2.4 nC/cm2 °C (comparable to single-crystal LiNbO3) and nonlinear optical coefficients comparable to d11 of crystal quartz are observed. Simple, inexpensive and fairly rugged pyroelectric detectors for electromagnetic radiation of any wavelength can be made from the poled films. Polyvinylidene fluoride (PVF2) crystallizes in a polar phase and it is found that its polarization can be switched. In the sense that it is a switchable pyroelectric PVF2 can be regarded as a ferroelectric polymer.