Inve~tigaci6n R.viAl. Muje.n. de Fl.lie. 39, No. ~ (1999) 581-587 Dye high power optical switch V. ABOITES, K.J. BALDWIN, G.J. CROFTS AND M .J. DAMZEN The Blaekett Labomlory, Imperial College Landon, SW7 2BZ, U.K. Recibido el 12 de enero de 1993; aceptado el 26 de abril de 1993 ABSTRACT.Experimental and numerical results are presented showing that a dye laser amplifier can be used as a very fast high power optical switch. The operation of the device is based on the fact that the absorption and transmission of the pump beam in the laser amplifier strongly depends on the intensity of the amplified signal beam [IJ. In particular it is shown that with relatively small signal beams it is possible to control large transmitted pump beams. A comparison between the numerical and the experimental observations show them to be in good qualitative agreement. RESUMEN. Se presentan resultados experimentales y numéricos que muestran que un amplificador láser de colorante puede ser usado como un interruptor óptico de respuesta rápida. La operación del dispositivo se basa en que la absorción y transmisión del haz de bombeo en el amplificador depende fuertemente de la intensidad de la señal láser amplificada [IJ. En particular se muestra que con haces de señal de relativamente baja intesidad, es posible controlar la transmisión de intensos haces de bombeo. La comparación entre los resultados numéricos y las observaciones experimentales mostró estar en buen acuerdo cualitativo. PACS: 42.60.Gd; 42.65.Pc; 42.65.Re l. INTRODUCTION As it is well known, most amplifier devices (e.g. vacuum tubes and transistors) can also be used as switching elements if they are operated in appropriate configurations. In particu- lar, laser pumped f1uorescent dyes have been widely used as amplifier media for incident laser signal beams at several wavelengths [2, 3]. More recently it has been shown [1] that in the steady-state the transmission of the pump beam through a laser amplifier can be strongly controlled by the intensity oC the signal beam. This steady-state result suggest that a laser amplifier can be used as an optical switch. In this communication the idea is studied numerically by solving the spatial and temporal system of equations which describe the atomic medium and the laser pump and signal beams. In order to obtain a elearer understanding of the dynamics oC the switching process the temporal-varying shape of reallaser pulses is taken into account. The results obtained show that an effective switching can be realized for the pump beam by a modulation in the signal beam incident in the amplifier and that the switching process occurring is very fasto These results were compared to experimental observations and were shown to be in good qualitative agree- ment. Nevertheless the overall efficiency of the process can be small due to excited-state absorption.