Fig. 1. Schematic of the proposed scheme. Two intense laser pulses interact on a subcritical density (n₀ = 0.1n_c) plasma layer at an angle θ = 10°.

Fig. 2. (a) Snapshot of normalized laser light field a_L(y, z, t) at time t = 14T₀. (b)–(d) Snapshots of electron density at times t = 14T₀, 18T₀, and 22T₀, respectively.

Fig. 3. Normalized laser light field a_L(y, z, t) (blue dotted line) and electron density (red solid line) along the y direction at (a) z = 9.5λ₀ and (b) z = 7.74 λ₀ at time t = 18T₀.

Fig. 4. Normalized laser light field (blue dotted lines) and electron density (red solid lines) along the y axis at different positions for two different scenarios. In (a) and (b), ultraviolet femtosecond laser light (λ = 260 nm) is used at a fixed angle of incidence of θ = 10°. (c) and (d) show the femtosecond laser light (λ = 800 nm) at time t = 15T₀ when the angle of incidence is modified to θ = 20°.

Fig. 5. Normalized electron density along the y axis for laser strengths a_L = 1 (yellow solid line), a_L = 3 (red solid line), and a_L = 5 (blue solid line).

Fig. 6. Trajectories of electrons in the EBC for (a) circularly and (b) linearly polarized laser pulses with the same laser intensity. The black dots represent the starting points of the electron trajectories. In (c), the normalized electron density of EBC along the y axis is presented, using the same laser and plasma parameters as in (a) and (b).

Fig. 7. Energy spectrum of EBC at t = 40T₀.