CO molecular orientation controlled by combination of chirped THz pulse and femtosecond laser pulse

In order to study the orientation behaviors of CO molecules induced by chirped terahertz pulse, the time-dependent Schrdinger equation was solved by means of rigid rotor approximation for theoretical analysis. In order to achieve high degree of molecular orientation in chirped terahertz pulse at a low intensity, the method by utilizing chirped terahertz pulse in combination with femtosecond laser pulse was proposed. The results show that the molecular orientation degree can be enhanced about 81%, and that the orientation efficiency decreases with the rise of temperature in finite temperature range. Compared with the few-cycle terahertz pulse, chirped terahertz pulse has more advantages in inducing molecular orientation. The result is meaningful to enhance the CO orientation degree.