Barry R. Masters

Ernst Abbe and the Foundation of Scientific Microscopes

Last year marked the 100th anniversary of the death of Ernst Abbe, who passed away on January 14, 1906-just a few days short of his 65th birthday. In addition to his groundbreaking optical work, which includes his diffraction theory for image formation and the formulation of the sine condition and Abbe number, he was also a noted entrepreneur, astronomer and social reformer.

Erwin Schrödinger’s Path to Wave Mechanics

In 1926, Schrodinger invoked Hamilton’s optical-mechanical analogy that related rayn optics and particle mechanics: His invention of wave mechanics related to particle mechanicsn as wave optics related to ray optics.

C.V. Raman and the Raman Effect

Barry Masters describes the life and legacy of one of the most important optical scientists of the 20th century.

Satyendra Nath Bose and Bose-Einstein Statistics

Although not as well known as his contemporaries, Satyendra Nath Bose wasn arguably one of the most important scientists in the 20th century. His revolutionaryn way of viewing photon behavior and photon statistics-later known as Bosen statistics-changed the field in a dramatic way.

Heinrich Hertz and the Foundations of Electromagnetism

Heinrich Rudolf Hertz did not grasp the practical importance of his workn during his lifetime, but his research into electromagnetic radiation laid then foundation for all wireless communications. The education and experience of thisn 19th century German scientist prepared him to make his monumental discoveries onn propagating electromagnetic waves.

A Brief History of Spectral Analysis and Astrospectroscopy

From Newton’s first insight into the composition of sunlight to the discovery of helium on the sun two centuries later, scientists’ work on the measurement and analysis of light has led to important discoveries that have greatly expanded our knowledge of physics, chemistry and astronomy.

Werner Heisenberg’s Path to Matrix Mechanics

In 1925, Werner Heisenberg—through a combination of intuition and sometimesn brilliant guesswork, and strongly influenced by the previous works of Einstein,n Ladenburg and Kramers—created his inchoate version of quantum mechanics.

Louis de Broglie and the Wave Nature of the Electron

Louis de Broglie was a Frenchman of noble birth who many believed would becomen a great statesman or diplomat. Instead, he changed our understanding of how then universe works by developing a theory for the wave-particle duality ofn electrons.

Single-Molecule Cellular Biophysics

Research on single-molecule cellular biophysics is an emerging field that is rapidly advancing based on the development of new instrumentation and experimental designs. To understand complex biological systems, researchers require instrumentation and techniques that span many orders of scale. The measured units include length, force, energy, time, and concentration and the validation of measurements for both in vivo and in vitro studies, as well as the limitations of the techniques and an understanding of the perturbations that the techniques induce in the experimental systems.

Adaptive Optics for Biological Imaging

It is fascinating how optical technology transfers among disparate fields of science and engineering. The history of adaptive optics is a good case study. The story begins in 1953 when a visionary, Horace Babcock, who was an astronomer at the Mount Wilson and the Palomar observatories, proposed a method based on adaptive optics to correct in real time the atmospheric distortions that degraded ground-based telescope images. All ground-based telescopes suffer from atmospheric turbulence, which causes time-dependent inhomogeneities in the air refractive index. They are caused by nonstationary random processes. The wind shears mix various atmospheric layers and the temperature inhomogeneities result in time-dependent variations in the refractive index of the air. They distort the wavefronts and thus degrade the image. One alternative is space-based telescopes such as the Hubble Space Telescope. Another is to implement Babcock’s idea of a closed-loop system incorporating a wavefront sensor and a deformable mirror that can introduce real-time changes in the wavefront to compensate for the aberrations introduced by the atmospheric turbulence. Babcock’s prescient ideas were developed into instrumentation in the mid-1970s and in 1982 the Defense Advanced Research Projects Agency (DARPA) working with the United States Air Force completed a real-time adaptive optics system integrated with an optical telescope on Maui in Hawaii. The motivation was to obtain high-resolution images of Soviet satellites. One common wavefront sensor is the Shack-Hartmann wavefront sensor, which works with white light and also with extended sources (such as the Sun). The closed-loop adaptive optics system involves computer wavefront reconstruction, which is a classical inverse problem whose solution can be found, but the solution cannot be proved to be unique.