Optically pumped ultraviolet molecular iodine laser

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Optically pumped ultraviolet molecular iodine laser

This content has been downloaded from IOPscience. Please scroll down to see the full text. 1977 Sov. J. Quantum Electron. 7 352 (http://iopscience.iop.org/0049-1748/7/3/L19) View the table of contents for this issue, or go to the journal homepage for more

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S. A. Keneman, Appl. Phys. Lett. 19, 205 (1971). V. I. Mandrosov, E. I. Pik, and G. A. Sobolev, Opt.. Spektrosk. 35, 131 (1973) [Opt. Spectrosc . (USSR) 35, 75 (1973)]. *Y. Obraachi and T. Igo, Appl. Phys. Lett. 20, 506 (1972). 5 V. V. Korsakov, V. I. Nalivaiko, V. G. Eemesnik, and V. G. Tsukerman, Zh. Tekh. Fiz. 44, 883 (1974) [Sov. Phys. Tech. Phys. 19, 565 (1974)]; Avtometriya No. 6, 24 (1974). 6 E. K. Watts, M. de Wit, and W. C. Holton, Appl. Opt. 13, 2329 (1974). 7 N. Uchida and N. Niizeki, Proc. IEEE 61, 1073 (1973). 8 E. M. Zolotov, V. A. Kiselev, and V. A. Syohugov, Usp. Fiz. Nauk 112, 231 (1974) [Sov. Phys. Usp. 17, 64 (1974)]. 8 E. J. Collier, C. B. Burckhardt, and L. H. Lin, Optical Holography, Academic Press, New York (1971). 10 W. J. Tomlinson, H. P. Weber, C. A. Pryde, and E. A. Chandrose, Appl. Phys. Lett. 26, 303 (1975). 3

"V. A. Kiselev, Kvantovaya Elektron. (Moscow) 1, 899 (1974) [Sov. J. Quantum Electron. 4, 495 (1974)]. 12 V. A. Kiselev, Kvantovaya Elektron. (Moscow) 1, 329 (1974) [Sov. J. Quantum Electron. 4, 182 (1974)]. 13 H. Kogelnik, Bell Syst. Tech. J. 48, 2909 (1969). 14 R. V. Schmidt, D. C. Flanders, C. V. Shank, and R. D. Standley, Appl. Phys. Lett. 25, 651 (1974). 15 D. C. Flanders, H. Kogelnik, R. V. Schmidt, andC. V. Shank, Appl. Phys. Lett. 24, 194 (1974). 16 Yu. A. Bykovskii, V. L. Velichanskii, V. A. Maslov, and V. L. Smirnov, Fiz. Tekh. Poluprovodn. 5, 939 (1971) [Sov. Phys. Semicond. 5, 825 (1971)]. 17 V. E. Wood, N. F. Hartman, C. M. Verber, and R. P. Kenan, J. Appl. Phys. 46, 1214 (1975). Translated by A. Bryl

BRIEF COMMUNICATIONS Optically pumped ultraviolet molecular iodine laser N. G. Basov, I. S. Datskevich, V. S. Zuev, L. D. Mikheev, A. V. Startsev, and A. P. Shirokikh P. N. Lebedev Physics Institute, Academy of Sciences of the USSR, Moscow (Submitted February 11, 1977) Kvantovaya Elektron. (Moscow) 4, 638 (March 1977) Stimulated emission was obtained in the region of 342 nm from molecular iodine pumped with radiation from an open high-current discharge. The active mixture had the composition I2:SF6:Ar = 0.004:0.13:1.5 atm. The stimulated emission lasted I jisec and it appeared 0.5 JASCC after the beginning of the discharge. PACS numbers: 42.55.Hq

The possibility of construction of gas lasers pumped optically by wide-band radiation and utilizing electronic transitions in molecules is discussed in Ref. 1. The molecule I2 is of considerable interest in this respect. The use of this molecule in a flashlamp-pumped laser is suggested in Ref. 2. The absorption of light in the 180-200 nm range transfers the I2 molecule from the ground state X'S* to the state Z/S* (Refs. 3 and 4). Collisions with molecules of other gases result in a transition to the nearby state 3 ng, followed by the emission of a photon at 340 nm and a descent to the state 3n2u. According to the FranckCondon principle, this transition terminates at high vibrational levels of the 'n^, state which may be emptied rapidly by the vibrational relaxation of the molecules. Stimulated emission as a result of the 'n^ — 'II^ transition in molecular iodine was first achieved as a result of electron-beam excitation of a mixture of argon and a substance containing iodine (such as CF3l). 5~7 In the present study we achieved laser emission from optically pumped molecular iodine. This was the first gas laser pumped by wide-band radiation and utilizing allowed electronic transitions corresponding to the ultraviolet part of the spectrum. The pump source was an open high-current discharge initiated by a tungsten wire 0. 5 m long. 8~10 The discharge was supplied from a 352

Sov. J. Quantum Electron., Vol. 7, No. 3, March 1977

capacitor bank (30 jiF) charged to 45 kV. The necessary concentration of molecular iodine was obtained by heating a stainless-steel chamber to 50 °C, corresponding to a saturated vapor pressure of about 3 Torr. We used an active mixture whose composition was I2 : SF6: Ar = 0.004 :0.13 :1. 5 atm. Sulfur hexafluoride was added to increase the electrical strength of the mixture and argon was used to ensure efficient transfer of the I2 molecules from the D'S* to the 'llj,, state. A resonator was formed by plane dielectric mirrors 4 cm in diameter with a reflection coefficient of 99% at X = 340 nm. The discharge was initiated at a distance of 2. 5 cm from the resonator axis and it expanded at a velocity of 3 km/sec. Stimulated emission occurred in a region which was not occupied by the discharge plasma. The laser radiation was recorded with a system comprising a STE-1 spectrograph, an SFR-2M quartz optics imageconverter camera operated in the streak mode, an FEU-39 photomultiplier with filters selecting the 290370 nm spectral range, and a FEU-52 photomultiplier which received light from a DFS-29 spectrograph that recorded radiation in a band 5 nm wide centered on X = 342 nm. Stimulated emission appeared after a delay of less than 1 fisec from the beginning of the discharge pulse and it Copyright © 1977 American Institute of Physics

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appeared simultaneously across the whole resonator mirror diameter. The rise time of the stimulated emission process was less than 0.1 p.sec. The spectral composition of the laser radiation was similar to that observed as a result of electron-beam pumping.7 The duration of stimulated emission was 1 j^sec. The laser action was probably quenched by the decomposition of molecular iodine by light within the photodissociation band. The existence of wide absorption bands and a slight Stokes shift suggested that it should be possible to build an efficient optically pumped tunable ultraviolet laser. The authors are grateful to Yu. S. Leonov for supplying the materials used. 'B. L. Borovich, Zh. Eksp. Teor. Fiz. 61, 2293 (1971) [Sov. Phys. JETP 34, 1228 (1972)]. 2 A. B. Callear and M. P. Metcalfe, Chem. Phys. Lett. 43,

197 (1976). J. A. Myer and J. A. R. Samson, J. Chem. Phys. 52, 716 (1970). 4 R. S. Mulliken, J. Chem. Phys. 55, 288 (1971). 5 M. V. McCusker, R. M. Hill, D. L. Huestis, D. C. Lorents, R. A. Gutchek,. and H. H. Nakano, Appl. Phys. Lett. 27, 363 (1975). 6 R. S. Bradford Jr, E. R. Ault, and M. L. Bhaumik, Appl. Phys. Lett. 27, 546 (1975). 7 A. K. Hays, J. M. Hoffman, and G. C. Tisone, Chem. Phys. Lett. 39, 353 (1976). 8 N. G. Basov, B. L. Borovich, V. S. Zuev, and Yu. Yu. Stoftov, Zh. Tekh. Fiz. 38, 2079 (1968) [Sov. Phys. Tech. Phys. 13, 1665 (1969)]. 9 N. G. Basov, B. L. Borovich, V. S. Zuev, V. B. Rozanov, and Yu. Yu. Stoilov, Zh. Tekh. Fiz. 40, 516, 805 (1970) [Sov. Phys. Tech. Phys. 15, 399, 624 (1970)]. IO B. L. Borovich, P. G. Grigor'ev, V. S. Zuev, V. B. Rozanov, A. V. Startsev, and A. P. Shirokikh, Tr. Fiz. Inst. Akad. Nauk SSSR 76, 3 (1974). 3

Translated by J. W. Brown

Possibility of formation of optical waveguides by laser and electron beam bombardment of thin glassy chalcogenide semiconductor films V. G. Remesnik, V. A. Fateev, and V. G. Tsukerman Institute of Automation and Electrometry, Siberian Division, Academy of Sciences of the USSR, Novosibirsk (Submitted April 12, 1976) Kvantovaya Elektron. (Moscow) 4, 639-641 (March 1977) An experimental investigation was made of the formation of directional waveguides by a laser or electron beam bombardment of thin evaporated glassy chalcogenide semiconductor films. When the change in the refractive index was maximized, it was possible to form optical waveguides with radii of curvature down to 0.1 mm and with bending losses of 0.2 dB/cm. Spatial separation of the guided modes was observed when the waveguide film was excited at an angle to the sloping edge of the film. PACS numbers: 42.80.Lt

Laser or electron beam irradiation of some glassy chalcogenide semiconductors is known to increase the refractive index n by up to 5% (Ref. 1). Thus, in films of this kind it is possible to produce refractive index profiles of arbitrary shape; this method was used in the recording of holograms and kinoform optical elements.2 The use of thin As-S films as waveguides was reported in Refs. 3 and 4, but integrated-optics elements were not formed in these films.

selected because it was characterized by the minimum losses at the wavelength just stated. The absorption coefficient increased with the percentage content of arsenic and scattering centers appeared when the sulfur content was raised. These films were evaporated in ~ 10~5 Torr vacuum by the electron-beam method. The rate of evaporation was kept constant at about 0.2 fi/min. The substrates were oxide glass plates with a refractive index

The present paper reports the first results obtained in a study of the formation of directional optical waveguides by irradiation of glassy chalcogenide films with laser and electron beams. We used evaporated As20S80 films, which were 0.4-6 M thick and had a refractive index « = 2.25. These films were excited with radiation of X = 0.63 ^ wavelength. This particular composition of the As-S system was 353

Sov. J. Quantum Electron., Vol. 7, No. 3, March 1977

FIG. 1.

Copyright © 1977 American Institute of Physics

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