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

¹ State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences - Shanghai 201800, China
² State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University - Changchun 130012, China
³ Graduate School of Chinese Academy of Sciences - Beijing 100080, China

^a huailiang@jlu.edu.cn
^b ya.cheng@siom.ac.cn
^c zzxu@mail.shcnc.ac.cn

Received: 7 January 2012
Accepted: 27 February 2012

Abstract

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 A²Π_u-X²Π_g 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.