Inverse energy flux of focused radially polarized optical beams

Formation of Inverse Energy Flux in the Case of Diffraction of Linearly Polarized Radiation by Conventional and Generalized Spiral Phase Plates

“…The general reasoning given in Section 3.1, as well as previous studies [17,18], shows that off-axis inverse energy flow can be greater than on the axis. This can be theoretically justified by using Equation (20) for the full phase p(ϕ):…”

“…The maximum relative negative value for Re[P z ] is observed when m = 2 and it is located at the origin. Note that, for integer m, the distribution of the real part P z is structurally similar to that for radial polarization of the mth order [17]. In both cases, the generated distributions are radially symmetric and there is a negative value on the axis only for m = 2.…”

“…However, the longitudinal distribution of the energy flow density is a key for realizing light fields with an inverse energy flux. The inverse energy flux phenomena [16][17][18][19][20] is related to "tractor beams" [21][22][23] in optical trapping and manipulation and to the detection of "invisibility cloaks" [24]. It should be noted that just one inverse energy flux does not guarantee the existence of the pulling optical force-the optical force can be negative due to the negative Poynting vector component, but its effect is often blocked by the gradient-phase force [25][26][27][28].…”

“…Earlier, the possibility of forming an inverse energy flux in the focal region for cylindrical vector beams (CVBs) of various orders was investigated, as was a linearly polarized beam with a cosine amplitude distribution [17,18]. Despite the existence of many methods for forming CVBs, linearly polarized laser sources remain the most readily available, affordable, and widespread.…”

Paraxial Propagation Properties of Radially Polarized Odd‐Pearcey Gaussian Beams in Free Space

“…[5,6] Radially polarized beams are excellent for cutting and micromachining of certain metals [7][8][9][10] and for trapping particles with high refractive index (e.g., metal nanoparticles) [11] because it can focus tightly. On account of the special focusing properties, nowadays the radially polarized beams are widely applied [12] for detecting the orientations of single molecules, [13] accelerating the charged DOI: 10.1002/andp.202100055 particles, [14][15][16] forming inverse energy flux, [17] and achieving the multiplexing of information transmission channels. [18,19] Additionally, the radially polarized beams are also considered as an ideal source for surface plasma excitation [20][21][22] and high resolution imaging.…”