Light Microscopy with Doughnut Modes: A Concept to Detect, Characterize, and Manipulate Individual Nanoobjects

Abstract

Higher order laser modes, mainly called doughnut modes (DMs) have use in many different branches of research, such as, bio-imaging, material science, single-molecule microscopy, and spectroscopy. The main reason of their increasing importance is that recently, the techniques to generate well-defined DMs have been refined or rediscovered. Although their potential is still not fully utilized, their specifically polarized field distribution gives rise to a wide field of applications. They are contributing to complete our fundamental knowledge of the optical properties of single emitting species, such as molecules, nanoparticles, or quantum dots, offering insight into the three-dimensional dipole or particle orientation in space. The perfect zero intensity in the focus center qualifies some DMs for stimulated emission depletion (STED) microscopy. For the same reason, they have been suggested for trapping and tweezing applications.

Electron vortices: Beams with orbital angular momentum

“…Since then, optical vortices have been intensively studied leading to many diverse applications (Allen et al, 2003(Allen et al, , 1999Andrews and Babiker, 2012), including optical tweezers and spanners for various applications (Dholakia et al, 2002;Grier, 2003;He et al, 1995;Ladavac and Grier, 2004): micromanipulation (Galajda and Ormos, 2001); classical and quantum communications (Yao and Padgett, 2011); phase contrast imaging in microscopy (Baranek and Bouchal, 2013;Fürhapter et al, 2005;Züchner et al, 2011); as well as further proposed applications in quantum information and metrology (Molina-Terriza et al, 2007;Yao and Padgett, 2011) and astronomy (Lee et al, 2006;Tamburini et al, 2011;Thidé et al, 2007). The discussion of photonic spin and orbital angular momentum in various situations, and the similarities and di↵erences between the two types of angular momentum have led to new ways of thinking about, and examining orbital angular momentum in this context.…”

Tuning the fields focused by a high NA lens using spirally polarized beams (Invited Paper)

“…First, an RPDB is realized using a liquid crystal MC (LQMC) according to the procedure described in Ref. [12]. Second, the polarization of the RPDB is uniformly rotated by angle β using a series of two λ∕2 retardation wave plates, where one is fixed while the other is free to rotate [13] .…”

“…[12]; thus, by mixing them with the MC setup shown in Fig. 1, all the possible combinations between the S and P polarized fields can be realized.…”

“…Moreover, the longitudinal component of RPDBs focused by a high NA lens, please refer to Ref. [12], is stronger than the transversal one. Thus, mixing RPDBs and APDBs is an easy way to obtain all of the special field configurations mentioned above, i.e., transversal polarization equal to longitudinal polarization and jE x j max ¼ jE y j max ¼ jE z j max , as well as many others.…”

“…(1), and the RPDBs and APDBs were calculated according to the procedure reported extensively in Ref. [12]. Furthermore, the SPDBs were considered to be monochromatic light sources (λ ex ¼ 633 nm) focused by an oil objective lens whose NA was fixed to be 1.25.…”