Laser dyes coumarin

The results from the study of the picosecond time resolved Stake s shift of the laser dye coumarin 480 in AOT/heptane-RMs [315] indicated that the water molecules in the water pool undergo slow relaxation on the nanosecond time scale. 

Jones, G., Jackson, W.R., Choi, C.Y., and Bergmark, W.R. (1985) Solvent effects on emission yields and lifetime for coumarin laser dyes. Requirements for the rotatory decay mechanism.. Phys. Cbem. 89, 294. 

Figure 3. Partial representation of frequencies available from the Nd. YAG fundamental (1) harmonics (2-5), YAG-pumped dye laser fundamental (Dye O), and stimulated Raman H2 and D2 shifts thereof. The Dye regions are approximations to the average envelopes of four dyes Coumarin 500, and Rhodamines 590, 610,...

Rhodamines (e.g. rhodamine 6G, rhodamine B) were among the first fluorescent dyes to be used as laser dyes. In contrast to coumarins, their absorption and emission spectra are quite narrow and the Stokes shift is small. They emit fluorescence in the range 500-700 nm. 

Examples of the optical pumping of solutions of luminescent conjugated polymers include laser action at 596 nm of poly[2-methoxy-5-(2-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) using excitation with 6 ns Nd YAG third harmonic pulses (354.7 nm). ° Tuning of hexane solutions of the co-polymer poly(2,2, 5,5 -tetraoctyl-p-terphenyl-4,4 -xylene-vinylene-p-phenylenevinylene) (TOP-PPV) was possible between 414 and 456 mn, similar to the classical coumarin laser dyes. ... 

Laser dye/Si02 gel CT AB/decanol/decane/ formamide (nonaqueous jjlE) TEOS/HzO (pH 1. HNO, coumarin 120 or coumarin 311) Preparation of silica gels doped with coumarin 120 and coumarin 311 (50)... 

In xanthenes, even if all one-photon allowed transitions are also two-photon allowed, the shape of the bands and their relative intensities are very different in the IPA and 2PA spectra [76,78]. This is not the case for other laser dyes and chromophores, for which the two spectra are almost identical (if represented as a function of the total transition energy), showing peaks in the same position and with very similar band shapes. Some example of chromophores in this category are coumarin 307 [78], coumarin 102 [80], 7-hydroxycoumarin [81], lucifer yellow [78], and cascade blue [78]. 

Coumarin, 4-alkyl-3-phenyl-3,4-dihydro- H NMR, 3, 583 Coumarin, 3-amino-synthesis, 3, 806 Coumarin, 7-amino-application laser dyes, 3, 879 fluorescence, 3, 879... 

The first systems without anomalous fluorescence discussed in the context of TICT states were coumarine laser dyes. Jones and coworkers208210 demonstrated that dialkylaminocoumarines like 7C showed an increase of the nonradiative decay rate in strongly polar solvents. This effect is dramatically increased if the acceptor properties of the coumarine skeleton are stronger, for example, in F7C. On the other... 

The main advantages of dye lasers are spectrum coverage (from less than 400 to 1000 nm) and tunability. In general, the laser dyes used nowadays have changed little from those used a decade ago [3]. Coumarins such as (73) and xanthenes such as Rhodamine 6G (74), are the main types. However, fluorinated coumarin dyes such as (75) have higher light stability than their nonfluorinated counterparts [39],... 

Most of the research over the past twenty years has been aimed at improving the performance of dye lasers by incorporating the laser dyes into a solid matrix [63], The choice of dye has the biggest effect on performance, with pyrromethine dyes having the best performance [64], Dyes such as Rhodamine 6G and Coumarin 540A have also been incorporated into an acrylic polymer matrix [65],... 

Fig. 13.38. Rhodamine (A), coumarin (B), oxazine (C), and syn-bimane (D) laser dye structures.

An illustrative example of solvent effects on absorption and emission spectra is given by the following positive solvatochromic laser dye 7-dialkylamino-4-(trifiuoromethyl)coumarin ( coumarin-153 ), in which the rotation of an amino group is restricted by incorporating it into a hexahydroquinolizine ring [341],... 

In addition, they are widely used as fluorescent molecules for laser dyes,14 in the emission layer in organic light-emitting diodes,15 and as the fluorophore in fluorescent sensors.1617 Their fluorescence properties are known to depend upon the nature and position of substituents, and therefore several groups have constructed coumarin libraries to discover better coumarin-based materials. 

Koefod, R. S. Mann, K. R., Preparation, photochemistry, and electronic-structures of coumarin laser-dye complex of cyclopcntadienylruthcnium(II), lnorg. Chem. 1989, 28, 2285-2290. 

Coumarins 3,4-annelated, synthesis and physiological activity of 82S337. Coumarins as active laser dyes 81YGK1200. 

Small organic molecules doped into polymer binders have also been employed in DEED devices. Coating is done using inexpensive solution techniques. A commonly used polymer is polyvinylcarbazole [50-52], which is a hole transport material with moderate mobility. Polysilanes have also been used as hole transport agents [53]. Common laser dyes may be employed as the emissive molecular dopant, for example coumarins [50, 51], rhodamines [50] or pyrans [51, 53]. Similar considerations of energetics and concentration apply to doped polymers as to small molecule dopant-host systems the dopant should provide the lowest energy site for the exciton and concentration quenching should be minimized. 

Among different coumarin derivatives used, 7-Amino-4-trifluoromethylcoumarin (ATFMC) revealed the most promising characteristics as an efficient fluorescent emitter. AFTMC is used in the synthesis of a substrate for fluorimetric assay of proteolytic enzymes and for use as a laser dye. We have recently investigated the chemiluminescence reactions of some peroxyoxalate esters, hydrogen peroxide and AFTMC. In this paper we report the solvent effects on the kinetics of the chemiluminescence process of the peroxyoxalate chemiluminescence in the presence of AFTMC. 

---