Photon-gated Spectral Hole Burning Research Articles

Persistent Spectral Hole Burning and Optical Properties of Sm2+ Doped in Mg0.5Sr0.5FCl0.5Br0.5 Mixed Crystal

A Sm 2+ -containing Mg 0.5 Sr 0.5 FCl 0.5 Br 0.5 mixed crystal was synthesized by firing at 1,100°C 2 hours in a reducing stream of hydrogen gas and examined with an X-ray diffractometer for the crystalline structure. We measured the optical properties of Sm 2+ -ion and observed the efficiencies of persistent spectral hole burning depend on hole burning methods at 90 K and 300 K. At 90 K, PSHB was made much more efficiently by using the photon-gated (two color) spectral hole burning process compared to the one color hole burning process, while the one color hole burning process is much more efficient at 300 K.

Spectroscopic analysis and persistent photon-gated spectral hole burning in LiF:F2− color center crystal

Luminescence and absorption spectra of LiF crystals with F2− color centers (CCs) were studied in the 14–300 K temperature range. The Huang–Rhys factors measured from absorption and emission spectra were equal in magnitude and calculated to be 3.2 and 2.72 at 77 and 300 K, respectively. It was shown that below 40 K inhomogeneous broadening of the zero phonon line of the F2− CC prevails over homogeneous broadening. Inhomogeneous broadening of the zero phonon line was observed to vary from 5 to 15 cm−1 for different crystal preparations. Persistent spectral hole burning stable at room temperature was realized in LiF:F2− crystals.

Inhomogeneous broadening and gated hole burning in MgS : Eu and CaS : Eu in polymethylmethacralate (PMMA)

Previously, we have reported on high-density photon-gated spectral hole burning in europium-doped alkaline earth sulfides. Enhanced inhomogeneous broadening of the zero phonon line (ZPL) has been achieved by embedding MgS : Eu 2+ and CaS : Eu 2+ in PMMA and by compacting the sample by other means. We investigate the inhomogeneous broadening as a function of the molecular weight and the concentration of PMMA. Changes in both the line shapes and the line widths of the ZPL were observed. With the enhanced broadening a much larger number of persistent power-gated holes have been burned in the ZPL.

Photon-gated spectral hole-burning and luminescence line narrowing of zinc tetraphenylchlorin in polymethylmethacrylate and in polystyrene

We have synthesized zinc tetraphenylchlorin (ZnTPC) by diimide reduction of tetraphenylporphyrin. We have observed photon-gated persistent spectral hole-burning for zinc tetraphenylchlorin in polymethylmethacrylate at liquid helium temperature. Even in absence of any acceptor additive, the hole formation is up to 5–6 times more efficient when two colours are absorbed by ZnTPC as compared to one colour excitation. Conversely, no gating effect was observed when ZnTPC is dispersed in polystyrene host matrices. On the other hand, the vibration spectra of ZnTPC in PMMA and PS were recorded using site-selection fluorescence and excitation techniques.

Electron transfer reaction of meso-phenyl-tetrabenzoporphyrinato-zinc and dicyanobenzene at low temperature

The behavior of photon-gated spectral hole burning with meso-phenyl-tetrabenzoporphyrinato-zinc as electron donor and dicyanobenzene as electron acceptor dispersed in polymethylmethacrylate was investigated. The data of absorption spectrum of the photoproduct acquired through photon-gated hole burning process by high power density and long hole burning time at 20 K were given. The mechanism of photoinduced donor-acceptor electron transfer for the target system in photon-gated spectral hole burning was demonstrated

HOLOGRAPHIC DETECTION OF PHOTON-GATED SPECTRAL HOLES AND IMAGE STORAGE

Holographic photon-gated spectral hole burning and image storage were performed in meso-phenyl-tetrabenzoporphyrinato-zinc/aromatic cyanide systems.In holographic spectral hole burning,the signal to noise ratio is improved considerably.Based on photon-gated persistent spectral hole burning,photon-gated frequency-selective multiple images were recorded and recalled successfully as holograms in the material.

Photophysical Properties ofMESO-Phenyl-Tetra-Benzo-Porphyrins and Photon-Gated Spectral Hole Burning in Mixed Donor-Acceptor Systems at Low Temperature

Abstract The photophysical properties of a series of compounds, meso-phenyltetra-benzoporphyrinato-Zinc (Zn-PnTBP, n=1-4) were presented. Multiple photon-gated spectral hole burning in the mixed donor-acceptor systems, Zn-P21–2TBP/DCB/PMMA was performed at 4.2 K and the mechanism of the photoinduced donor-acceptor electron transfer reaction at 20 K was elucidated.

Non-destructive readout of picosecond time-and-space-domain holograms recorded by photon-gated spectral hole burning

Two-color photon-gated persistent spectral hole burning in zink tetrabenzoporphine with a solid halocarbon additive 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane in polystyrene film at liquid-helium temperature has been used for recording of picosecond photochemically accumulated stimulated photon echo (PASPE) holograms. In the presence of the gating illumination at 532 nm the hole-burning yield increased by a factor of up to 100. With the gating illumination switched off we were able to read out the recorded time-and-space-domain holograms for a long time and with high intensity practically without destroying the contrast of the recorded information.

Photon-gated spectral hole burning in Pr^3+:YAG

We observed photon-gated spectral hole burning in Pr:YAG and assigned the hole-burning mechanism to selective photoionization of trivalent praseodymium. Gated holes were observed in absorption lines to the two lowest components of the (1)D(2) manifold. At 1.4 K the gating ratio is in excess of 1.5 x 10(4). Strong competition from the transient mechanism of optical pumping of hyperfine levels occurs below 6 K.

The observation of photoproducts and multiple photon-gated spectral hole burning in a donor-acceptor and a donor 1 + donor 2-acceptor system

Multiple photon-gated spectral hole burning and photoproducts were observed in two systems: zinc-tetrabenzoporphyrin/crotonic acid/phenoxy resin film and zinc-tetraphenyl-benzoporphyrin+zinc-tetraphenyl(4-phenyl-acetylamino)benzotribenzoporphyrin/phydroxybenzaldehyde/poly(methyl)metacrylate film. The hole burning sequence, whether burned successively from the shorter wavelength side to the longer side or the opposite, and the selection of suitable intensities of burning and gating laser were proved to be important in high quality multiple hole formation. Their photoproducts after hole burning are cation radicals of their corresponding electron donors. The photon-gated spectral hole burning processes are determined to be donor-acceptor electron-transfer reactions.

Spectral hold burning in the Soret absorption band of a zinc tetrabenzoporphin derivative

The results of photon-gated spectral hole burning in the Soret absorption band of a Zn tetrabenzoporphin derivative in poly(methylmethacrylate) are reported. Zero-photon holes are formed throughout the whole Soret band via the photon-gating technique. The electron-photon coupling in both the first S 1 and second S 2 excited singlet states is shown to be approximately equal; the Huang-Rhys factor is 0.3. The zero-phonon holewidth yields an S 2 state lifetime of 1.7 ps at 20 K. A strong correlation between S 0S 1 and S 0S 2 transitions was observed with the correlation coefficient ϱ = 0.981.

Thermally activated barrier crossing and hole-filling in donor-acceptor electron transfer systems

An electron donor-acceptor-doped polymer for photon-gated spectral hole burning (PHB) was described as a two-level system (TLS). Thermal hole-filling was studied by the temperature cycling experiment. A thermally activated barrier crossing model in a TLS is used to explain the hole-filling process was verified by numerically fitting between the theoretical and the experimental results. The maximum barrier heights in several PHB materials were obtained.

A study on multiple photon-gated persistent spectral hole burning and photoproduct in a system of frequency-domain storage material

This paper reports recent advances in the study on multiple photon-gated spectral hole burning and its photoproduct in a system of Zn-tetrabenzoporphin-crotonic acid-phenoxy resin at liquid helium temperature. The influences of gating-light inducing hole-erasing and satellite holes causing hole-filling on the formation of multiple holes are analyzed. A spectrum of more than 100 multiple photon-gated spectral holes burnt over a whole absorption band is presented. The photoproduct after hole burning was also observed indicating the hole burning process to be donor-acceptor electron transfer reaction.

Photon-gated spectra hole burning in a mixed meso-phenyl-tetrabenzoporphyrinato-zinc/aromatic cyanide system and hole filling induced by a gating beam

Photon-gated spectral hole burning in mixed meso-phenyl-tetrabenzoporphyrinato-zinc as donor in which the inhomogeneous line width of mixture reaches 370 Å, with aromatic cyanide as acceptor in poly (methylmethacrylate) has been performed at 4.2 K. The hole filling induced by a gating beam was studied. The absorption of the gating beam by donor molecules leads to both broad-band bleaching of the S 1 ← S 0 inhomogeneous line before hole burning and hole filling after hole burning.

Linear Electron-Phonon Interaction in Organic Spectral Hole-Burning Materials

The linear electron-phonon interaction in polymethylmethacrylate (PMMA) doped with electron donor zinc-tetraphenylbenzoporphyrin (ZnTPBP) and acceptor p-hydroxybenzaldhyde (PHBA), or p-aminoacetophenone (PAAP) was investigated by photon-gated spectral hole-burning (PHB). The aim is to study the factors that affect the linear electron-phonon coupling and the thermal stability of spectral holes in the organic film samples.

Photon-gated spectral hole burning by donor-acceptor electron transfer in poly(methylmethacrylate) copolymers containing covalently bound chloroanthracene and doped tetraphenylporphine

We report two-color photon-gated spectral hole burning systems mentioned in the title via donor-acceptor electron transfer. In these systems, the acceptor, 10-chloroanthracene, was branched to a side-chain of the poly(methylmethacrylate) (PMMA) host polymer while the donor, metal-free tetraphenylporphine, was dispersed in the polymer. Spectral holes were burnt when the systems were simultaneously irradiated with a frequency selective excitation (wavelength: ca. 643 nm; duration: 500 ps; energy: 200 nJ/cm2) and a gating excitation (wavelength = 514.5 nm; duration = 33 ms; energy = 14 μJ/cm2). The thermal stability of burnt holes measured with a temperature cycling experiment increased when the acceptor was branched into PMMA.

Photon-gated spectral holeburning

Photon-gated spectral holeburning uses two photons to bleach a narrow hole in an inhomogeneously broadened absorption. A brief review is given of the inorganic and organic materials known to exhibit this phenomenon, with emphasis on the inorganic systems BaClF:Sm 2+, CaF 2:Sm 2+, LiGa 5O 8:Co 2+ and SrTiO 3:Cr 3+. In all these cases photoionization of the impurity ion is believed to be the mechanism of photobleaching.

Photon-gated spectral hole burning by donor-acceptor electron transfer

We have observed a new mechanism for photon-gated spectral hole burning, donor-acceptor electron transfer, in a material composed of a zinc-tetrabenzoporphyrin derivative (donor) with chloroform acceptors in poly(methyl methacrylate) thin films. Gated holes form when we simultaneously excite the donor 0-0 singlet absorption (630 nm) and the donor triplet-triplet absorption (350-550 nm), with the largest gating enhancement (>30) occurring for gating light near 480 nm. The gating action spectrum and the photoproduct spectrum confirm that the mechanism is electron transfer from an excited triplet of the porphyrin donor to the chloroform acceptor. This result opens up a new class of materials for photon gating that should be of interest for frequency-domain optical storage applications as well as high-resolution spectroscopy of electron transfer processes in solids.

Two-color, photon-gated spectral hole-burning in an organic material

We report the first observation of two-color, photon-gated spectral hole-burning in an organic system: carbazole in boric acid glass. This novel hole-burning mechanism involves stepwise biphotonic photoionization of carbazole at 1.4 K. The quantum yield for photoionization increases exponentially with the energy of the second photon.

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

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.