Direct-Write Digital Holography. Development and research of a hologram printer

TL;DR

This paper presents the development of a digital hologram printer capable of producing high-quality, white-light viewable transmission holograms using a novel optical system and speckle reduction techniques.

Contribution

It introduces a one-step monochromatic hologram printer design with a microlens array and feedback system, advancing digital holography technology.

Findings

Optimized lens system enhances hologram contrast and depth of view.

Microlens array effectively reduces speckle effects.

Temperature-energy feedback stabilizes pulsed laser output.

Abstract

Chapter 1 gives a brief history of the field of holography along with an overview of this thesis. A more detailed description of holography is provided in Chapter 2 along with a discussion of digital holography. Chapter 3 examines the design of a one-step monochromatic hologram printer capable producing white-light viewable transmission holograms created with the aid of an LCOS display system and printed in a dot-matrix sequence. The lens system employed includes a microlens array and an afocal relay telescope which are both quantitatively examined in order to maximise the contrast, diffraction efficiency and depth of view of the final hologram image. A brief overview of speckle reduction techniques and their applicability to pulsed digital holography is presented along with experimental results of the use of a microlens array to reduce speckle effects. Chapter 4 presents an analysis of the unwanted side effects of the angular intensity distribution of a hologram pixel, using a case study for analysis. Chapter 5 examines methods for increasing both the printing speed and resolution of the hologram printer. Chapter 6 describes the analysis and design of a temperature-energy feedback system to correct for pulsed laser instabilities arising from mode beating due to temperature variations. Chapter 7 provides a conclusion to the work and discusses possible future developments.