title: Techniques for measuring small changes in the intensity of a pulsed laser.
abstract: Several techniques are described that compensate for the pulse-to-pulse laser fluctuations that occur when small absorption or gain measurements are taken with pulsed lasers. The best approach tested used two matched diodes that were mounted in a bridge circuit with their bias batteries. One diode was illuminated by a single beam, and a second was illuminated by a reference beam. The bridge circuit output forms the difference in the two laser intensities. Using pulsed lasers with 8-ns widths, we observed that the error in subtraction was 0.01% of the pulse area. This was only 1.5 times the shot noise of the pulses. The technique is examined for application to Raman-induced Kerr-effect spectroscopy, in which difficulties arise because of the use of polarization-sensitive detection.
authors: J
authors: J
authors: Borysow
authors: H
authors: H
authors: Golnabi
authors: R H
authors: RH
authors: Taylor
authors: J W
authors: JW
authors: Keto