The generation of intense ultrashort light pulses in mode-locked laser systems has made possible a wide range of new experiments designed to study the interaction of light with matter. For the quantitative interpretation of the results, accurate measurement of the optical pulse structure is essential, and it is the purpose of this paper to review all the diagnostic techniques currently available. The recent rapid development of the electron-optical streak camera is highlighted, while considerable space is devoted to an extensive description of the many second- and higher order correlation measurements (including the popular two-photon fluorescence method). A discussion of ultrafast shutter techniques is also included, together with a section on pulse chirping and dynamic spectroscopy.

Ultrashort pulse measurements

Picosecond optical pulses provide a unique means for studying ultrafast processes associated with the interaction of light with matter. Implementation of these studies has required the development of new measurement techniques capable of picosecond time resolution. In this chapter, we describe the various methods that are now available for characterizing picosecond laser pulses and for detecting rapid events created by them. Our emphasis here is on the relative advantages and limitations of the techniques themselves and less on the results of particular experiments. An understanding of these techniques is necessary for proper evaluation of any picosecond experiment. Many inconsistencies in early work have been due not only to the variability of pulsed laser sources but to improper interpretation of experimental results. As the various pitfalls of picosecond measurement become better understood, experimental studies become more reliable. At the same time, a better understanding of ultrafast process will undoubtedly lead to new and better measurement techniques.

Techniques for Measurement

Mode-locking of lasers

Full intensity profile analysis of ultrashort laser pulses using four-wave mixing or third harmonic generation

Publisher Summary This chapter discusses the mutual dependence between coherence properties of light and nonlinear optical processes. The chapter is concerned with the mutual relationship between nonlinear optical effects and the coherence properties of light, a subject that seems to be gaining increasing importance, because of the recent development both of new high-power sources and sensitive and fast detection devices. If a medium is irradiated by light, changes of the state of the medium, as well as of the statistical properties of light, will be caused by nonlinear interactions. The chapter presents a concise compilation of relations concerning the coherence of light, by means of which the physical meaning of the classical and quantum-theoretical description is discussed in connection with experimental techniques and measuring procedures. The chapter explains the treatment of several important multiphoton processes such as multiphoton absorption, two-photon emission, optical parametric processes, and stimulated Raman scattering. In connection with the discussion of these effects, representative theoretical and experimental methods are outlined and employed in the chapter.

III The Mutual Dependence Between Coherence Properties Of Light And Nonlinear Optical Processes

Measurement of picosecond pulse shape by three-photon fluorescence

Passive mode-locker and Q-switch for ruby

Passive mode locker and Q-switch for ruby

An image‐converter streak camera incorporating a TV video‐recording system interfaced to a computer HP 2100 was used to record and instantly display the processed shape of a picosecond laser pulse. The output versus input exposure response curve linearity of the whole system was verified over a dynamic range of at least 10. Performance testing of the system was done using a cw mode‐locked YAG laser.

A. Novotny

Papers

Measurement of picosecond pulse shape by three-photon fluorescence

Passive mode-locker and Q-switch for ruby

Passive mode locker and Q-switch for ruby

Nearly on-line picosecond streak camera diagnostics of the cw mode-locked YAG laser radiation.