Bessel beam based optical profilometry

Abstract

We present our results of the development of some schemes for nondestructive optical profilometry of cylindrically shaped surfaces by using spatially matched conical light beams. A theoretical model is elaborated which describes profilometers with Bessel beams. A special feature of the profilometers proposed is the possibility to control their sensitivity and resolution. To this end, a scheme of tuning the cone angle of the Bessel beam over a wide range is incorporated. The operation regime of the profilometers is characterized by a nonzero spatial frequency of output signal. It allow us to apply a new algorithm for the interpretation of the output signal. This algorithm consists in the calculation of the azimuth spectrum which characterizes the deviation of tested profiles from the circular ones

Influence of scattering media on the regular structure and speckle of quasi-nondiffractive Bessel light beams

“…This property is promising for practical applications requiring the laser beams with large focal depth, including interferometry of cylindrical objects [4,5], coherence tomography [6], optical manipulation of microparticles [7][8][9], etc. For example, the combination of propagation invariance and reconstruction of the axial maximum allows one to realize an optical interconnection of inline circuit boards [3].…”

Determination of microrelief of the sample by singular beams superposition

“…The salvation of peculiarities mentioned above leaded to the searching of methods based on using of Bessel and Laguerre-Gaussian beams. [15,16] where the dependence of rotation angle for intensity distribution of so-called "twolobed fields" were investigated in dependence on the depth of focus for spiral beams as well as influence of amplitude and phase distortions on the formation of the light field with the intensity rotation was established. [17].…”

Quasi–Nondiffractive Beams for OCT–Visualization: Theoretical and Experimental Investigations

“…From the viewpoint of foresaid the growing interest to various types of quasi-nondiffractive light beams (for example, a Bessel beam) is caused by the availability of unique properties: the large focal length of the beam, the suppressed diffraction divergence of the central part of the beam inside the focal length, the reconstruction of the transversal structure of the beam at the shielding of its central zone and a submicron structure of the axial maximum (for a nonparaxial and evanescent Bessel beam). These properties are promising for practical applications requiring the laser beam with a large focal depth, including the interferometry of cylindrical objects (Belyi, et al, 2005;Dresel, et al, 1995), the coherent microscopy (Leitgeh et al, 2006),the optical manipulation of microparticles (Arit, et al, 2001;Garces-Chavez et al, 2002), etc. Together with advantages referred above Bessel beams have several drawbacks due to the feature of shaping units .…”