Owing to the remarkable field confinement ability, surface plasmons have become an ideal platform for investigating light-matter interactions at the sub-wavelength scale. The intriguing properties make surface plasmons the fundamental block for future optoelectronic applications, including biomedical detection, photocatalysis, nanolaser, and data storage. Notably, the aforementioned fundamental and application research calls for surface plasmons with large tunability. Conventionally, the properties of surface plasmons can be tailored by changing the size, shape, environmental refractive index, and gap of the structure. However, these methods are usually static and lack of flexibility.

Recently, the advance of light field manipulation has expanded the dimension of light utilization and provided rich and flexible strategies for regulating light-matter interactions. For example, through the amplitude, phase, and polarization modulation of the light field, a variety of super-resolution imaging techniques have been developed. Precise control of molecular rotation, dissociation, and ionization can be achieved by employing the time domain regulation of the light field. By controlling the coherence and polarization state of the light field, the conversion efficiency of nonlinear optical processes can be improved. Correspondingly, these methods for controlling the light-matter interactions have also been successively applied to surface plasmons, which open up a new way for exploring novel phenomena and developing related applications.

The eigen-response theory is first introduced to describe the polarization matching method to selectively excite plasmonic modes. We show the typical work on the tuning of dipole moment orientation [Fig. 2(b)] and the excitation of plasmonic dark modes (Fig. 3) with the aid of vector beams. The plasmonic mode controlling enables the generation of a strong local field to precisely manipulate the light-matter interactions at the single molecular level [Fig. 4(a)] and enhance the efficiency of surface-enhanced Raman spectroscopy [Fig. 4(b)]. Additionally, the nanosize particles with ultrasmall hot spots are trapped [Figs. 4(c) and 4(d)], and the optical upconversion frequency of a plasmonic octamer is tuned [Fig. 4(e)].

Subsequently, the mechanism for controlling plasmonic mode coupling is explained in the frameworks of plasmon hybrid theory (Fig. 5) and coupled harmonic oscillator model (Fig. 6). Specifically, we present the work on controlling the bonding and antibonding modes of the plasmonic dimer with vector beams [Fig. 7(a)]. In 2010, Volpe et al. demonstrated a method to deterministically control the local field of the plasmonic nanostructure. They employed the optical inversion algorithm to superpose the Hermit-Gaussian beams with different amplitudes and phases to construct the vector excitation and successfully produce the target local field distribution as shown in Fig. 7(b). Meanwhile, we emphasize the excitation progress of single and multiple Fano resonances in highly symmetric plasmonic nanoclusters using the vector beams [Figs. 7(c) and 7(d)]. In addition, we show the applications of controlling plasmonic mode coupling in the optical binding force reversion [Fig. 8(a)], enhanced second harmonic generation [Fig. 8(b)], and the detection of structural defect and beam misalignment [Fig. 8(c)].

Finally, the method to control the far-field scattering of plasmonic structures with vector beams is interpreted by combing Mie theory and Kerker condition. As an example, we show that the unidirectional scattering of a core-shell plasmonic nanosphere can be achieved by adjusting the phase differences and amplitude between electric and magnetic dipoles (Fig. 9). Interestingly, the tightly focused radially polarized beams can excite a spinning dipole moment in an Au nanosphere [Fig. 10(a)]. The polarization distribution at the focal plane allows for tuning the emission from a homogeneous to a unidirectional pattern by simply moving the particle relative to the beam axis [Fig. 10(b)], which is found to have an application in the directional coupling to a planar two-dimensional dielectric waveguide [Fig. 10(c)]. Additionally, Zang et al. demonstrate a method to realize the asymmetric excitation of surface plasmon polaritons (SPPs) by illuminating a pair of slot antennas with the Hermite-Gaussian beam [Fig. 10(e)]. They summarized the asymmetric intensity ratio of the SPP pattern as a displacement function of slot antennas [Fig. 10(f)], delayering a displacement sensor with angstrom precision.

We briefly introduce the basic theory and physical mechanism of the interactions between vector beams and plasmonic modes and review the recent progress of plasmon mode excitation, coupling, and far-field radiation regulated by the vector beams. Furthermore, their applications in enhanced spectroscopy, nanometric optical trapping, and nano-displacement sensing are introduced. It is worth noting that the research on light field manipulation is still in a rapid development track, and some new types of light fields have been emerging, such as the superchiral optical needle, photonic skyrmions with topological features, and optical M?bius strips. These advances provide great opportunities for people to control plasmonic modes with extra freedom. Meanwhile, ultra-compact plasmonic structures represented by plasmonic nanocavities have emerged as a promising route to squeeze light into the true nanoscale level. It is foreseeable that if the merits of these two aspects are combined, one will have more abundant strategies to manipulate the optical properties of surface plasmons, ranging from the mode volume and optical chirality to the local optical density of the state. In this sense, it would open up a new avenue for studying basic physical phenomena such as strong coupling at room temperature, optical nonlinearity, and polarization-dependent optomechanics. Then, it will undoubtedly expand the applications of surface plasmons in information, energy, biology, and many other fields.