摘要:

During tha eight years since phthalocyanine solution was used by Sorokin and Lankard in the original dye laser1and DTTC bromide and iodide were used in the work of Schafer, Schmidt and Volze2, laser emission has been reported3from close on 400 combinations of laser dye and solvents covering a wavelength range extending from 340 to 1175 nm. Many hundreds or even thousands of attempts to induce laser action in a vast number of available chemicals have proved unsuccessful, either by pulsed or continuous laser pumping, or by flashlamp techniques. In fact, relatively few combinations have established themselves as highly efficient, reliable and entirely satisfactory dye laser media. The compound rhodamine 6G is probably the most widely used in the range 540–640 nm. However, some ten different solvents and a variety of excitation techniques have been necessary to maintain maximum fluorescence intensity over this range. A t shorter wavelengths an acidic solution of 4,6- dimethyl-7-methylamino-coumarin in ethanol was observed to lase4over the range 430–530 nm and a particular solution of 4-methylumbelliferone to lase from 391 to 567 nm5. This offered the possibility of achieving narrow linewidth tunability using dye lasers based on single solutions. It represented a significant advance on the first experiments2in which it was possible by changing the solvent, varying the solute concentration or changing the reflectivity of the resonator mirror, to Shift the wavelengths by up to 60 nmm in the infra-red region.

ISSN:0038-7010    

DOI:10.1080/00387017508067390

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

A very simple, but accurate opto-electronic method is proposed for studying the characteristics of photographically recorded spectral lines. The experimental apparatus consists mainly of a He-Ne laser, an oscilloscope and inexpensive optics which permits the precise study of line profiles, line-width, intensities and the measurement of wavelengths by means of comparison with a standard spectrum.

ISSN:0038-7010    

DOI:10.1080/00387017508067391

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Selective laser excitation of a specific isotopic species to its lowest electronic singlet (S1) and triplet (T1) states respectively, then followed by a chemical reaction for isotope separation is examined theoretically. It is found that the direct excitation to T1state from ground state (S0) is an unique excitation channel for obtaining a controllable chemical reaction and for achieving a high isotope separation factor. This is due to the following important facts: 1) Resonant energy transfer from a selectively excited triplet isotopic species to an unexcited species of the other isotope present in the mixture is missing (or is very small); 2) The lifetime of the T1state is normally longer than that of the S1state; 3) There is no intersystem crossing channel that exists for the deactivation of excited isotopic species from T1state.

ISSN:0038-7010    

DOI:10.1080/00387017508067392

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The internal kinetics of NO2as well as the kinetics of crossover between CH3F and NO3were studied in mixtures of these polyatomics and rare gases.

ISSN:0038-7010    

DOI:10.1080/00387017508067393

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Experimental findings concerning liquid state relaxation processes of electronically excited molecules, coming from time-resolved spectroscopy and travelling wave dye lasers, offer a formidable basis for restructuring some of the theories dealing with relaxation processes. Comparison of the prime research literature with standard texts shows a severe time lag in the dissemination of essential concepts, while comparison of ‘traditional’ fluorescence with intra-cavity photon emission reveals basic differences involving relativistic effects and vector space construction, mitigating against the practice of directly incorporating laser based data into ordinary chemical dynamics.

ISSN:0038-7010    

DOI:10.1080/00387017508067394

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

ISSN:0038-7010    

DOI:10.1080/00387017508067395

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

ISSN:0038-7010    

DOI:10.1080/00387017508067389

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor