Optical devices with silica-gel small spheres

Some inexpensive optical devices using small silica-gel spheres are presented. The silica-gel spheres of good quality are investigated under the microscope. These sphere presents some particularities which make them very useful in applications like interferometry, hygrometry and optical microscopy. Such small spheres may be doped with microcrystals or dye solution in order to study a large range of nonlinear phenomena. Experimental studies have been performed on the silica spheres as alternative media for laser action using a pulsed CuBr laser as excitation source.