Holography, after some oscillation in its early history, appears to have settled down to a pattern of sustained growth. Commercially important applications are emerging.

Holography has been enjoying an explosion of public interest over the past two years, especially as the number of three-dimensional laser photographs in peoples' homes has increased dramatically. Underlying this public perception of progress has been an authentic and gradual development of holographic imaging technology, but it is fair to say that holographers are still struggling against the same fundamental constraints as they were more than ten years ago. In business, "timing is everything," and the recent events in holography are largely business phenomena (it has always taken a lot of patience to be a holographer, and no less so in these matters!). In this discussion, we will attempt to draw out a few of the long-term threads of holographic progress that underlie the recent good news.

This paper provides a review of non-holographic display devices. Pertinent aspects of the human visual system are briefly discussed in relation to the design of devices for display of three-dimensional data. Several technologies which have now reached relative maturity are discussed. A broad scope of applications strongly drives new developments, and the present state-of-the-art is considered.

This paper discusses current knowledge of the behaviour of silver halide materials as recording media for holographic images. The work is structured so as to crystallise the contribution of certain key workers in the field. It is shown that despite early pessimism about the performance capability of the silver halide, experimental achievement is of a high order of finesse with only minor advances to be expected overall in the use of such media to achieve high diffraction efficiency. The approach of Soviet scientists to the problem of image modulation has led to an essential dichotomy of technique between East and West; the 'brown' and 'black' silver technologies. These differences are highlighted and important areas demanding further progress are outlined.

A brief background is provided for the fields of particle and flow visualization holography. A summary of methods currently in use is given, followed by a discussion of more recent and unique applications. The problem of data reduction is discussed. A state of the art summary is then provided with a prognosis of the future of the field. Particle and flow visualization holography are characterized as powerful tools currently in wide use and with significant untapped potential.

This paper describes the current status of nonoptical holography. The majority of applications are in nondestructive testing utilizing ultrasonic energy, with a few using electromagnetic radiation. These applications and methods will be described, and the latest results presented.

Hologram interferometry is a technique of optical measurement that grew out of laser holography in the mid 1960's. This paper reviews its discovery and traces its evolution over the past two decades. Emphasis is placed on the revolutions it has created both in interferometry and mechanics.

Computer holography is a rich field which appears to be in its infancy. We offer here a review of hologram methods and requirements as well as a discussion of present and future applications.

Holographic optical elements (HOEs) and computer generated holograms (CGHs) offer many attractive properties and uses. In this review, we consider the use of holography in pattern recognition, with specific attention to recent work with CGH elements.

This article will review some of the current applications of real-time holography. No claim is made of thoroughness; the field is too diverse. Instead, this article will focus on some of the more recent, interesting, and promising applications of real-time holography.

One of the most rewarding applications of holography is the teaching of it. Because of its highly visual nature, holography can be introduced at any level to practically any age group with a broad spectrum of educational backgrounds. However, a rigorous understanding of this subject, even at a non-mathematical level, requires the basic study of physical optics on topics such as interference, polarization, coherence, etc.--subjects not normally taught except in physics courses. Herein we demonstrate a series of pedagogic techniques through which all of these phenomena can be presented, using the simplest of equipment. Artists without any technical background can be initiated into this field through this rudimentary introduction and begin to explore a new medium of expression.

The present status of activities of research and application of holography in Japan is reviewed. The most active field is metrology, and many applications in automobile, aircraft, electronic industries as well as basic researches are found. Information processing and optical memory are still in laboratory level, and suitable applications are looked for. Optical elements are promising, and applications in POS scanning systems are already in practical use. Applications in 3-D image display are spreading among the public, and applications for medical purpose have started. Acoustical holography is applied in mechanical engineering, and electron holography becomes a very attractive tool for experimental physics.

The importance of holography in Europe is herein described through the status of photosensitive materials, holographic optical elements, holography in security printing, holographic interferometry, and holographic display. Many examples of industrial and medical applications are reviewed, and so are applied research and basic studies carried in laboratories.