Photon-gated hole burning: a new mechanism using two-step photoionization

Abstract

We have observed photon-gated spectral hole burning, i.e., hole burning that occurs only in the presence of an additional gating-light source. Gating enhancement factors of 10(4) were observed. In BaClF:Sm(2+) this involves two step photoionization of Sm(2+) and leads to persistent holes in the (4)F(0) --> (5)D(0) (687.9-nm) and (7)F(0) --> (5)D(1) (629.7-nm) absorption lines. The hole widths of 25 MHz at 2 K are much narrower than the inhomogeneous broadening of 16 GHz. The action spectrum of the gating shows a threshold behavior around 2.5 eV. Erasing studies show that Sm(3)+ acts as a trap for the released electrons. A remarkable and novel feature is that the holes can be recovered after temperature cycling to 300 K.

Laser Light-Induced Physical Processes In Optical Materials: Persistent Spectral Hole-Burning

“…In photon-gated PHB, two photons (of different wavelengths) are required for the photoinduced change leading to hole-burning (writing). In recent experiments, photon gated PHB has been observed for the first time for Sm + 2 ions in BaC1F crystals [28]. The mechanism is thought to be that shown schematically in Figure 7.…”

“…This discovery shows that materials exist that can relieve one of the most serious concerns with frequency domain optical storage: volatility of the stored data. Further experiments are in progress to understand this novel process, and the *' , reader is urged to consult the references for more detail [28].…”

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

“…(Photon-gated storage has not been experimentally demonstrated for TDOS but the scheme suggested above should be a straightforward extension of photongated storage in FDOS. 23 ) In the reading process the atoms transferred to the reservoir state then cannot be excited to the upper state, as a wavelength different from that of the read pulse would be needed. The branching ratio with no gating pulse should be very small, preferably zero.…”

“…tional higher limit is T2 T < 2 (22) be stored An addi- (23) This limit ascertains that the N bits are written in a time less than the homogeneous dephasing time of the transition, T 2 . Inequalities (19)- (23) determine the possible bit rate as a function of the number of bits stored in each single point (assuming nondestructive reading), and the storage density may be used as a parameter in inequalities (20) and (21 Number of bits/point Fig.…”

Dynamical Hole-Burning Requirements for Frequency Domain Optical Storage

“…This discovery shows that materials exist that can relieve one of the most serious concerns with frequency domain optical storage: volatility of the stored data. Further experiments are in progress to understand this novel process, and the reader is urged to consult the references for more detail [31].…”