Fig. 1. Schematic of (a) a dual-pillar DLA and (b) a multichannel DLA. Two laser pulses (propagating in ±x directions) incident on the DLA are indicated by the orange arrows. Electrons travel inside parallel channels along the z direction.

Fig. 2. (a) Illustration of the photonic crystal where the unit cell is highlighted in the dashed red box. The electron propagation direction is indicated by the gray arrow. 2a, 2b, 2d, and L represent pillar length, pillar width, gap width, and the periodicity in the electron propagation direction, respectively. (b) The reciprocal Brillouin zone. (c) Band diagram of the TM mode of the photonic crystal with L=1  μm, a=0.3  μm, b=0.86  μm, and d=0.2  μm. Big (small) black dots represent eigenmodes with odd (even) mirror-z symmetry, and red (blue) dots represent eigenmodes with even (odd) mirror-x symmetry. (d), (e) Field profiles of the eigenmodes at the Γ point with normalized frequency 0.500 and 0.411, respectively.

Fig. 3. (a) Schematic of the dual drive simulation. The dashed box highlights the unit cell, the red arrows represent the illuminating lasers, and the gray arrows indicate the electron propagation direction. Under in-phase and equal amplitude illumination at wavelength λ0=2  μm, the magnitude of E field is shown in (b), while Ez, Ex, and Z0Hy are shown in (c), where Z0 is free-space impedance.

Fig. 4. (a) Longitudinal and (b) transverse force distribution inside each electron channel. (c) Amplitudes of the cosh and sinh components in each channel at central frequency and (d) their frequency dependence.

Fig. 5. (a) Bandwidth of the MIMOSA versus number of electron channels. The geometric parameters are the same as those studied in Section 3. (b) The corresponding pulse duration of a transform-limited Gaussian pulse with central wavelength 2 μm and a bandwidth matching the bandwidth of the MIMOSA.

Fig. 6. (a) Band diagram of a photonic crystal deflecting structure with L=1  μm, a=0.26  μm, b=0.66  μm, and d=0.2  μm. The symbols have the same meaning as in Fig. 2(c). The field profiles of the deflection mode at the Γ point with normalized frequency 0.5 (indicated by the blue arrow) are shown in (b).

Fig. 7. Field distributions in the three-channel deflecting-mode MIMOSA under antisymmetric excitation. (a) Electric field amplitudes; (b) field components Ez, Ex, and Z0Hy.

Fig. 8. Longitudinal and transverse force distributions in a deflecting-mode MIMOSA are shown in (a) and (b), respectively, with the proper electron phase that maximizes each force. (c) Amplitudes of the cosh and sinh components in different channels at central frequency; (d) their frequency dependence.

Fig. 9. Schematic of a multichannel centralizer. With symmetric excitation, the transverse forces inside the electron channels are indicated by the small red arrows. The gray arrows indicate the trajectories of electron beams.

Fig. 10. (a) Band structure of the infinitely periodic photonic crystal underlying the electron centralizer. The periodicities in the z and x directions are L=1  μm and Lx=1.52  μm, and the dimensions of the rectangular pillar are a=0.26  μm and b=0.56  μm. The green arrow indicates that the incident frequency is within the band gap. With symmetric excitation, the electric field amplitudes are shown in (b), while the nonzero field components Ez, Ex, and Z0Hy are shown in (c).

Fig. 11. MIMOSA functioning as a centralizer. (a) and (b) show the longitudinal and transverse forces, respectively, with the electron phases that maximize the longitudinal or transverse forces. The amplitudes of the cosh and sinh components are shown in (c), and their frequency dependence is shown in (d).

Fig. 12. MIMOSA with 10 electron channels. (a) and (b) show the longitudinal and transverse forces in different channels. The amplitudes of cosh and sinh components in different channels are shown in (c), and their wavelength dependence is shown in (d). Different colors indicate different channels. Due to the mirror-x symmetry, channels above x=0 are omitted in (d).

Fig. 13. MIMOSA with high acceleration factor but small bandwidth. (a) The band structure of the photonic crystal (L=1  μm, a=0.32  μm, b=0.82  μm, d=0.2  μm). The red arrow points to the acceleration mode. The band containing the acceleration mode is highlighted in green. (b) The field distribution of the acceleration mode. (c) The pulse duration of the transform-limited Gaussian pulse, whose bandwidth matches the bandwidth of the MIMOSA, as a function of the number of channels.

Fig. 14. Particle tracking simulations of 500 attoseconds FWHM bunch with initial emittance of 0.1 nm and charge of 2 fC showing (a) final emittance after propagating through the 15 μm MIMOSA structure and (b) corresponding fraction of transmitted particles as functions of externally applied focusing field K. Only the center channel of the MIMOSA is shown since the results for the three channels are nearly identical.

Fig. 15. Particle tracking simulation of (a) centroid angular deflection ⟨x′⟩ and ⟨y′⟩ and (b) fraction of transmitted particles for a 20 μm long three-channel MIMOSA operating in deflection mode. The initial beam parameters are the same as for the acceleration case considered in Fig. 14, with space charge and external focusing turned off. Deviation of the deflection curve from a linear relationship is due to truncation of particles by the aperture of the channel at higher incident field.