Multiwavelength amplified harmonic emissions from carbon dioxide pumped by mid-infrared femtosecond laser pulses

We demonstrate multiwavelength amplified harmonic emissions in carbon dioxide gas driven by intense mid-infrared femtosecond laser pulses. The simultaneous amplified emissions at 315, 326, 337 and 351 nm from the A2Πu-X2Πg transition of CO2+ are found to have a high gain coefficient of ~4.43 cm−1 with the polarizations parallel to that of the pump laser. This is ascribed to the seeding effect by the third harmonic of pump laser. The coherence property of the amplified harmonic emissions is further evidenced by its diffraction pattern.