The HHG spectrum from an argon atom by the BCCP laser field when the wavelength of the right-circularly polarized laser is varied from 100 nm to 900 nm, while the wavelength of the left-circularly polarized laser is fixed at 800 nm (ω₁ = 0.056 a.u.). The solid blue and purple horizontal lines indicate that the wavelengths of the right-circularly polarized laser fields are 800 nm (ω₂ = ω₁) and 400 nm (ω₂ = 2ω₁), respectively. The four dotted red lines from top to bottom represent the wavelength of right-circularly polarized laser are 533 nm (ω₂ = 1.5ω₁), 320 nm (ω₂ = 2.5ω₁), 228 nm (ω₂ = 3.5ω₁), and 177 nm (ω₂ = 4.5ω₁), respectively.