The Revolution in Femtosecond Near-infrared Pulse Generation

The field of ultrafast pulse generation is rapidly developing as a result of advances in material science and technology. As a result, average power, tunability and versatility of near infrared femtosecond sources is increasing. In the midst of this frenetic activity, we pause to discuss how the field has developed to the present state and consider the implications for future source developments as well as requirements for experiments. There remain a number of important unsolved problems in this area, and present sources are still inadequate for many experiments.