| Popis: |
We introduce new figures of merit (FOM's) for resonant optical materials used in recording, storage, and processing of optically encoded information using coherent optical transients. The goal is to account for maximum coherence storage time as well as for efficiency of the light matter interaction quantified using the ratio between the rate of dephasing and the rate of spontaneous radiative decay. Highest FOM values are achieved when the dephasing rate approaches the fundamental limit set by spontaneous emission under the condition that the total transition oscillator strength is concentrated between a single pair of energy levels. In this case, the information (both classical and quantum) can be transferred from the radiation field to the storage medium and back at the fastest possible rate, while the loss of optically prepared coherence is minimized. We analyze FOM's of some of the most promising rare-earth-doped crystals at cryogenic temperatures and show that the homogeneous line width may approach the radiative limit in some cases even when the peak cross section remains below the fundamental limit. |
