It has been over 5 years since the last special section on polarization appeared in Optical Engineering. In the intervening years, there has been tremendous progress and a strong resurgent interest in polarization in remote sensing, phenomenology, and devices. Military applications have driven much of the interest in remote sensing and phenomenology, while commercial interests, particularly in the area of telecommunications, have driven development of devices and new metrology capability. These requirements have demanded new instrumentation, new theories, and population of phenomenology databases. Tremendous capability in instrumentation has resulted over the last decade due to cheaper and more capable opto-electronics and cheaper and far more powerful computing power. The increased computing power has enabled the sophisticated data reduction and calibration that is required when making polarimetric measurements. The new instrumentation, which has been used to better understand the phenomenology associated with light in nature and in optical systems, has enabled better understanding and experimental verification of theories and models.

This special section encompasses the breadth of polarization. The 16 papers of the special section can be broadly grouped into four categories: instrumentation, analysis, measurements, and instrumental polarization. Six papers on instrumentation range from non-imaging spectral instruments to imaging instruments to polarization simulators covering the spectrum from the visible to the long wave infrared. Two papers refine polarization effects in instrumentation and describe instrumental polarization analytically and experimentally. Five analytical papers cover many areas of concern to people working in the area of polarization, particularly with regard to scattering theory, optimizing Mueller matrix measurements, and noise effects in polarimetric systems. Finally, three papers cover measurements including detection, discrimination, and phenomenology.

Interest in polarization continues to grow. Biannual polarization conferences at SPIE have recently become annual conferences. SPIE conferences on polarization now include Vol. 891 held in 1988, Vol. 1166 in 1989, Vol. 1317 in 1990, Vol. 1746 in 1992, and Vol. 2265 in 1994. Recent conferences are documented in Vol. 3121 (1997), Vol. 3754 (1999), Vol. 4133 (2000), and Vol. 4481 (2001). Many of the papers in this special section are updated versions of work documented in these proceedings. An SPIE-sponsored Polarization Technical Group was formed in 1999 and continues to grow with annual meetings, a web site, and a discussion forum. Polarization has also garnered interest in other conferences including IEEE, OSA, and Military Sensing Symposia (MSS).

Acknowledgments

The special section editors would like to thank Karolyn Labes, managing editor of Optical Engineering, for her assistance in preparing this special section. The editors would also like to thank the authors for their hard work in preparing these papers and the reviewers for their diligence and (unpaid) devotion to the scientific process of peer review.