There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Current medical imaging technologies allow visualization of tissue anatomy in the human body at resolutions ranging from 100 micrometers to 1 millimeter. These technologies are generally not sensitive enough to detect early-stage tissue abnormalities associated with diseases such as cancer and atherosclerosis, which require micrometer-scale resolution. Here, optical coherence tomography was adapted to allow high-speed visualization of tissue in a living animal with a catheter-endoscope 1 millimeter in diameter. This method, referred to as "optical biopsy," was used to obtain cross-sectional images of the rabbit gastrointestinal and respiratory tracts at 10-micrometer resolution.

In Vivo Endoscopic Optical Biopsy with Optical Coherence Tomography

In this paper, we summarize the fundamental properties and review the latest developments in high power fiber lasers. The review is focused primarily on the most common fiber laser configurations and the associated cladding pumping issues. Special attention is placed on pump combination techniques and the parameters that affect the brightness enhancement observed in single-mode and multimode high power fiber lasers. The review includes the major limitations imposed by fiber nonlinearities and other parasitic effects, such as optical damage, transverse modal instabilities and photodarkening. Finally, the paper summarizes the power evolution in continuous-wave and pulsed ytterbium-doped fiber lasers and their impact on industrial applications.

High Power Fiber Lasers: A Review

A topical review of numerical and experimental studies of supercontinuum generation in photonic crystal fiber is presented over the full range of experimentally reported parameters, from the femtosecond to the continuous-wave regime. Results from numerical simulations are used to discuss the temporal and spectral characteristics of the supercontinuum, and to interpret the physics of the underlying spectral broadening processes. Particular attention is given to the case of supercontinuum generation seeded by femtosecond pulses in the anomalous group velocity dispersion regime of photonic crystal fiber, where the processes of soliton fission, stimulated Raman scattering, and dispersive wave generation are reviewed in detail. The corresponding intensity and phase stability properties of the supercontinuum spectra generated under different conditions are also discussed.

Supercontinuum generation, photonic crystal fiber

In this paper, we summarize the fundamental properties and review the latest developments in high power ytterbium-doped fiber (YDF) lasers. The review is focused primarily on the main fiber laser configurations and the related cladding pumping issues. Special attention is placed on pump combination techniques and the parameters that affect the brightness enhancements observed in high power fiber lasers. The review also includes the major limitations imposed by fiber nonlinearities and other parasitic effects, such as optical damage, modal instabilities and photodarkening. The paper summarizes the power evolution in continuous-wave (CW) and pulsed YDF lasers and their impact on material processing and other industrial applications.

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High power ytterbium-doped fiber lasers — fundamentals and applications

The fields of optics and photonics have experienced dramatic technical advances over the past several decades and have cemented themselves as key enabling technologies across many different industries. This paper explores past milestones, present state of the art, and future perspectives of several different topics, including: lasers, materials, devices, communications, bioimaging, displays, manufacturing, and industry evolution.

Optics and Photonics: Key Enabling Technologies

The fields of optics and photonics have experi- enced dramatic technical advances over the past several decades and have cemented themselves as key enabling technologies across many different industries. This paper explores past milestones, present state of the art, and future perspectives of several different topics, including: lasers, materials, devices, communications, bioimaging, displays, manufacturing, and industry evolution.

Optics and Photonics: Key Enabling Technologies Thispaperreviewsthepast,present,andfuturevisionofthetechnologiesofopticsand photonics, including lasers, materials and devices, communications, bioimaging, displays, manufacturing, as well as the evolution of the photonics industry.

Given the breadth of technical and application areas that have been significantly touched by optics, experts with different backgrounds were invited to give a snapshot of the field from their individual vantage points.

Henry Kressel

Papers

Optics and Photonics: Key Enabling Technologies

Optics and Photonics: Key Enabling Technologies Thispaperreviewsthepast,present,andfuturevisionofthetechnologiesofopticsand photonics, including lasers, materials and devices, communications, bioimaging, displays, manufacturing, as well as the evolution of the photonics industry.

Prolog to the Section on Optics and Photonics