In the field of coherent control, the phase controlled optical dissociation of molecules is one of the most interested subjects. To break specific bonds in the molecules, one method is to efficiently deposit laser energy into the vibrational modes causing the vibration to grow in amplitude until dissociation is achieved. One way to achieve such excitation is to use short, intense, chirped laser pulses in the mid-IR region. On the other hand, especially for the case of non-polar, symmetric molecular bonds, we should use Raman process to overcome the selective rules to vibrationally excite specified bonds. It is called RCAP. The raman process uses two opposite chirped pulses to highly excite the vibrational mode of a diatomic molecule. The two pulses must have a wavelength difference corresponding to the vibrational level spacing.
- We report an alternative technique for generating two synchronized, intense pulses that is based on the amplification of a dual-wavelength oscillator.
- A number of dual-wavelength , mode-locked Ti:Sapphire oscillators were recently developed. They give the appropriate wavelength separations for the coherent control techniques, but one must amplify the pulses to carry out these experiments.
- We have developed a chirped pulse amplification system that simultaneously amplifies pulses from both beams of a dual-wavelength oscillator in a single regenerative amplifier.
In conclusion, a dual-wavelength chirped-pulse amplification system is an ideal tool to coherent control techniques. The laser system delivers two synchronized, high-intensity, independently tunable pulses. At present, the laser system generates a total energy of 1.5mJ that can be variably split between the two pulses. The wavelengths can be tuned over the 800-890nm region. The pulses are 150 fs in duration and have a 60 fs timing jitter.