Excerpt from Radiometric Methods for Measuring Laser Output Key Words: Laser, radiometry, laser energy measurement, radio metric calibration, photoelectric photometry, optical attenuator. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

The output of pulsed lasers may be measured with reasonable accuracy by modifications of established radiometric methods. The receiver, thermopile or phototube, is used ballistically. It is calibrated by an incandescent-lamp standard of spectral irradiance. The laser beam is attenuated to make its irradiation on the receiver comparable to that from the calibrating source. Attenuation is accomplished by intercepting the entire laser beam on a diffusely reflecting surface. The attenuation factor is determined from direct measurement of the reflectance of this diffusing surface and the geometric constants of the system. The accuracy of the measurement of laser output is dependent upon the accuracy of calibration of the standard of spectral irradiance and the accuracy with which the spectral sensitivity of the receiver, the spectral transmittance of the band-pass filters, and the reflectance of the diffuser can be determined. Measurements made with different photoelectric receivers agree to about 1.5% using a 1/4-joule pulsed ruby laser as a source. Total uncertainty is estimated to be about 5%. Measurements made using these radiometric methods have been compared with calorimetric measurements and a discrepancy of 9% was observed. (Author.

Excerpt from A Pyroelectric Power Meter for the Measurement of Low Level Laser Radiation, Vol. 6 The decision to develop the laser power meter described here resulted from need with the laser industry for a rapid, convenient means of low level measuring laser power. It was originally encouraged by T. W. Russell who was responsible for the Laser Measurement Assurance Program. The work was performed under the supervision of R. J. Phelan, Jr., Optical Electronics Program Leader. Others who gave substantial assistance to the project were L. O. Mullen, K. W. Pyatt, G. P. Klein, Y. Beers, and Debra Deichman. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

The revised 2nd edition of this practical book provides an expanded treatment and comparison of techniques used in advanced optical measurements, guiding its reader from fundamental radiometric and photometric concepts to the state-of-the-art in highly sensitive measurements of optical losses and in spectroscopic detection using coherent laser light and spontaneous radiation. The book describes and compares a broad array of high-sensitivity methods and techniques – from interferometric and/or calorimetric, acousto-optic and resonator or polarization to wavelength- and frequency-modulation, phase-shift and decay time studies, and direct-loss measurements for free-space, fiber- or waveguide-based systems and devices. Updated throughout, the new edition describes novel trends in spectral interferometry, frequency-comb and laser-excitation spectroscopy, reflected in the developments of Raman, Brillouin and FTIR (Fourier Transform Infra-Red) techniques for biomedical research, biotech sensing and detection. It also covers broad practical implementations of time- and frequency-domain terahertz spectroscopy measurements. This book reviews the physical concepts of radiation transfer, providing a quantitative foundation for the means of measurements of optical losses, which affect propagation and distribution of light waves in various media and in diverse optical systems and components. It focuses on the application of optical methods and procedures for the evaluation of transparent, reflecting, scattering, absorbing, and aggregated objects, and for determining the power and energy parameters of radiation and color properties of light. This updated new edition will serve as an up-to-date reference source and practical guide for those using photometric and radiometric techniques.