A versatile and stable device allowing the efficient generation of beams with radial, azimuthal or hybrid polarizations

Radially and azimuthally polarized nonparaxial Bessel beams made simple

“…Moreover, the interest for these complex polarization field configurations does not limit only to the linear optics case, as azimuthally polarized spatial dark solitons have been proved to be exact solutions of Maxwell's equations in Kerr-type nonlinear media [15]. All these reasons have motivated the development of several experimental techniques to realize such field configurations [16][17][18][19][20]. Recently, it has been also shown that squeezed azimuthally polarized optical beams show hybrid entanglement [21].…”

Saturated structured confocal microscopy with theoretically unlimited resolution

“…Devices such as those proposed in Refs. [30][31][32] could be inserted into the illumination arm of the confocal set-up in order to produce the desired polarization state required for recording the second image. We believe that such a rather simple implementation may attract the attention of experimentalists interested in high-resolution fluorescence imaging.…”

Fiber-modes and fiber-anisotropy characterization using low-coherence interferometry

“…Due to the high dynamic range of the InGaAs camera, we were able to resolve all transverse fiber modes using an appropriate offset of the excitation without any additional frequency-filtering electronic circuit to enhance the visibility of the interference fringes [4]. A simple algorithm using the interference maximum and minimum was used to reconstruct the mode profile and to calculate the mode intensity: the intensity of the interference signal of the two arms I nr , the intensity of the nth fiber mode I n , and the intensity of the reference beam I r follow the relation I nr = I 0 + I r + I n + 2 I r I n cos ϕ (6) where I 0 is the intensity of all other fiber modes, the optical paths of which do not match the optical path of the reference arm; the intensity of the reference beam I r was obtained at the beginning of the measurement by blocking the fiber arm; ϕ is the relative phase between the two beams which might depend on transverse position, giving rise to the appearance of fringes in the detected image; I nr was obtained by the camera in real time. According to the N -bucket phase-shifting method [20] we used the following algorithm to find the interference maximum and minimum, and hence, the mode intensity distribution,…”

“…Several fiber techniques have been developed to generate such beams while employing higher-order modes of respective shapes [5][6][7]. A full characterization of the mode profiles as well as the polarization state of these modes is essential to successfully apply these novel techniques.…”