Real-time optical waveform convolver/cross correlator

Abstract

We show that an inhomogeneously broadened sample, excited by a series of three resonant optical pulses, emits an optical signal whose electric field envelope closely approximates the convolution or cross correlation of the field envelopes belonging to two of the three excitation pulses. The convolution (cross correlation) function is obtained when the first (second) pulse in the excitation sequence is short compared to the temporal structure of the other two excitation pulses.

Recording density limit of photon-echo optical storage with high-speed writing and reading

“…The reason that this is not the case can be seen in Eq. (2). The pulses are assumed to be Fourier limited, and since it is implicitly assumed in the model that the laser intensity is increased such that the pulse area is unchanged when the pulse is shortened, the number of atoms that are affected by the excitation pulse is inversely proportional to the bit duration.…”

Incorporating excitation-induced dephasing into the Maxwell–Bloch numerical modeling of photon echoes

“…The unique properties of these materials for storage and data processing applications [1][2][3][4] arise from the combination of this narrow homogeneous line width, a broad distribution of such resonances (the inhomogeneous line width), and long coherence times (the time during which the ions that share a resonance frequency respond collectively).…”

Demonstration of a continuous scanner and time-integrating correlator using spatial–spectral holography

“…Spatial-spectral holography (SSH) has previously been used to implement signal correlation by recording the spectral interference between a temporal correlation reference waveform and a time-delayed brief impulse as a modulation of the spectral grating, and then reading it out with the signal to be correlated and observing the stimulated photon echo in time [1]. The temporal duration of the stored reference is limited by the coherence time, T 2 (typically 10-100 ms), the readout duration is limited by the excited state lifetime, T 1 (10 ms in Er 3þ ), or bottleneck state lifetime, T B (10 ms in Tm 3þ ), and the processing gain is limited by the ratio of signal bandwidth (or inhomogeneous bandwidth if that is smaller) to homogeneous line width.…”