Abstract
Wide use of infrared (IR) lasers in technological applications (metal cutting and hardening, laser evaporation, laser bending and etc.) have stimulated a research in the field of synthesis of IR-range diffractive microoptical focusing elements, Which could retain their functionality under continuous irradiation with high power. Successive fulfillment of this requirement is stipulated both by selection of an appropriate substrate material and by development of technologies for creation a diffractive microrelief oil a substrate as well as numerical methods for microrelief optimization taking into account possible technological constraints.
The present chapter contains a consideration of modern approaches to the synthesis of diffractive optical elements (DOE) for technological IR-laser beams focusing.
Experimental results of produced elements investigation described also.
Different ways, from geometrical optics approximation to stochastic optimization, are used for calculation of a diffractive microrelief of IR-range optical elements that focus all illuminating beam into a pre-given 2-dimensional area. Near-IR DOE synthesis oil sapphire substrates by plasmochemical etching method is considered.
Several diamond focusing DOEs for operating at CO2-laser wavelength (lambda = 10.6 mu m) are produced and presented. The nanosecond UV-laser ablation and plasmochemical lithographic etching technologies for DOE synthesis on CVD diamond plates are discussed.
Being a perspective optical material, CVD diamond has a high refractive index (n=2.4), resulted in relative high losses by Fresnel reflection. The present chapter includes consideration of a realization of antireflecting structures on a diamond film surface by UV-laser ablation.
The advent of silica and silver-halide IR-range optical fibers for technological applications has set tasks of optimization methods development and of forming diffractive microreliefs on optical fiber surface for waveguide beam controlling. The present chapter includes the results of experimental investigation of diffractive microrelief and antireflecting structures that are realized on an end-face of IR-fiber.