ABSTRACT

As ultrafast lasers find their way into new applications areas, there remain some technological barriers to realizing their full potential. One of the key issues for practical applications of ultrafast lasers is the implementation of an adjustable time delay between optical pulses or between an optical pulse and a signal to be measured. The manifold applications of ultrafast lasers described in this book exploit various properties of the ultrashort pulses, such as high peak power, short coherence length, broad bandwidth, or, of course, the short pulse duration. This chapter is most relevant to applications that utilize the high speed of ultrashort pulses for various types of time-resolved measurements. Generally speaking, these applications can be classified into two main categories: (1) pump-probe measurements and (2) external signal measurements. Highspeed sampling of optical waveforms for telecommunications is an example of the latter type. An incoming signal from a device under test (DUT) is sampled using an ultrashort laser pulse from a local laser. This requires various kinds of asynchronous sampling techniques. Here, however, we concentrate on laser systems that can be used for the first type of measurements system, i.e., a pump-probe system.