Fluidic laser beam shaper by using thermal lens effect

Influence of natural convection on beam propagation in fluidic optical device

“…Ar ion laser, of which wavelength is 488 nm, was used. The dye called sunset-yellow has significant absorption spectra at the wavelength of the laser [11]. In the experimental system represented in Fig.…”

“…In addition to these measurement researches, change of the beam profile itself is also of interest recently. Taking advantage of the thermal lens effect, we have developed the fluidic optical device as a flexible beam shaper [11][12][13]. One major characteristic of the fluidic optical device is that it can be used for both spatial and temporal laser beam shaping.…”

“…One major characteristic of the fluidic optical device is that it can be used for both spatial and temporal laser beam shaping. Doan et al [11,12] demonstrated the principle of the spatial beam shaper by means of the thermal lens effect and an application to Bessel beam generation system. In their study, it was confirmed that various beam profile could be easily obtained by controlling pump beam power.…”

Thermal lens in a liquid sample with focal length controllable by bulk temperature

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In this paper, we propose a new solution, which is an improvement to recent propositions given in [9][10][11]. In contrast to many of the above-cited ideas, which rely on modification of the lens shape, one can induce a refractive index distribution, ∇n, that acts as a lens, without changing the shape of the lensing element.

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“…As shown by the authors of Refs. [9][10][11], ∇n formation can lead to the formation of a few millimetre (thus macroscopic)-size aperture thermal lenses whose focal length depends on the heating laser intensity. However, the authors of these two works did not take into account that ∇n at a selected heating laser intensity can depend as well on the bulk temperature of the thermal lens element, irrespective of this element being a liquid [9, 10] or solid [11].…”