The Response of Inhomogeneously Broadened Optical Absorbers to Temporally Complex Light Pulses.

George L. Lamb

William Randall Babbitt, Yu Bai, THOMAS W. MOSSBERG

We discuss the light signals that are coherently emitted by some optical absorbers sub-sequent to excitation by a series of three laser excitation pulses. In some cases, the light signal emitted by the material duplicates the temporal shape of one of the laser in-put pulses. In other cases, the emitted signal represents the convolution or cross-correlation of two of the laser input pulses. In principle, digitally encoded signals of multi-gigahertz bandwidth can be convolved in real time, or, in suitable materials, stored for long periods. Output signals on the order of a few percent as intense as the inputs are possible. We provide experimental demonstrations of these effects, and discuss their implementation in optical signal processing and data storage systems.

George L. Lamb

K.D. Merkel, William Randall Babbitt

Summary form only given. Accurate true-time delays are essential to correctly steer modern phased-array antennas. Optical coherent transient technology has the ability to store a variable true-time delay as a spatial-spectral holographic population grating in an inhomogeneously broadened absorber (IBA). Typically, two optical pulses program the delay. A third optical pulse or waveform applied to the IBA generates a delayed replica of itself. The delay is typically defined by /spl tau//sub 21/=t/sub 2/-t/sub 1/, the arrival time difference of the first two pulses. However, we find that this prediction for the delay of the emitted signal only holds for input optical pulse areas much less than pi. Experimental investigation and simulations were performed to observe the variation in arrival time of the output signal.

William Randall Babbitt, Yu Bai, THOMAS W. MOSSBERG

It has been pointed out that inhomogeneously broadened absorbers can remember and be stimulated to reproduce, through the emission of free-induction-decay signals, the temporal shapes of laser pulses to which they have been exposed,1 This process possesses a certain intrinsic novelty and may also represent an alternative approach to realizing frequency-selective optical data storage.2

Md. Aminul Islam Talukder