Controllable mode transformation in perfect optical vortices

Abstract

We report a novel method to freely transform the modes of a perfect optical vortex (POV). By adjusting the scaling factor of the Bessel-Gauss beam at the object plane, the POV mode transformation can be easily controlled from circle to ellipse with a high mode purity. Combined with the modulation of the cone angle of an axicon, the ellipse mode can be freely adjusted along the two orthogonal directions. The properties of the "perfect vortex" are experimentally verified. Moreover, fractional elliptic POVs with versatile modes are presented, where the number and position of the gaps are controllable. These findings are significant for applications that require the complex structured optical field of the POV.

Centrosymmetric Optical Vortex

“…Furthermore, the mode purity ε is a significant parameter which can reveal the quality of the generated CSOVs. In our experiments, the mode purity was estimated via the correlation coefficients between the experimental intensity pattern and the numerical simulation intensity pattern [16,30]. As shown in Figure 3a1,a2, the values of the mode purity ε are both greater than 0.9, which indicates that the CSOVs still maintain a high beam quality.…”

“…For instance, an off-axis factor is brought in OVs to generate a series of asymmetric light fields, such as asymmetric Bessel modes [12], asymmetric Laguerre-Gaussian beam [13], and asymmetric Gaussian optical vortex [14]. Furthermore, to increase the mode distributions of the perfect OV, the elliptic perfect OV has been reported recently, which is regulated via a scaling factor [15,16]. Moreover, by modulating the phase gradient and the phase jump factors, the power-exponent-phase vortex [17] and the remainder-phase optical vortex [18] are generated, respectively.…”

Controlled Mechanical Motions of Microparticles in Optical Tweezers

“…Typical controllable methods of particles motions via using optical tweezers are to scan a point-like optical trap with rotating mirrors [ 39 , 40 , 41 ], galvanometer-driven mirrors [ 42 , 43 , 44 ], acousto-optical deflectors (AOM) [ 45 , 46 , 47 ], and spatial light modulator (SLM) [ 48 , 49 , 50 ]. Due to the optical gradient forces, particles will follow closely with the moving beams.…”

Generation of reconfigurable optical traps for microparticles spatial manipulation through dynamic split lens inspired light structures

“…Once the control parameters are set at will to design a tailored light cone, the next step is to create a top-opening in the structure, in order to let the microparticles to fall inside the light cone. Methods to generate holes in light bottles were addressed by different authors 28 , 39 . In our case, this step is conducted as illustrated in Fig.…”