ABSTRACT
This chapter discusses femtosecond laser pulse generation. The simplest recipe for femtosecond pulse generation is to create a coherent bandwidth and to synchronize all the frequencies within the bandwidth so that their phases coincide at a given time. The generation of shorter pulses requires very broad bandwidths, exceeding 100 nm, and titanium-doped sapphire is the material that has proven capable of generating sufficient bandwidth to directly generate sub-5-fs pulses. The most successful approach to mitigating self-action processes to date is known as chirped-pulse amplification (CPA). More recently, amplification has been accomplished by using a nonlinear optical crystal that is pumped by an intense long-duration pulse. The chirped input pulse is then amplified through a parametric process that can support very broad bandwidths. These amplifiers are known under the name Optical Parametric Chirped Pulse Amplifiers. In summary, femtosecond pulse generation requires an oscillator capable of creating highly stable seed laser pulses.
