1. For a general review see Bertolotti, M. and Vitali, G. in Current Topics in Materials Sciences, vol. 8 ed. E. Kaldis, Amsterdam, North-Holland Pu. Co., 1982, p. 95.
2. Carmichael, C.H. and Simpson, G.N., Nature 202 (1964) 787; Birnbaum, M., J. Appl. 36 (1965) 657; Bell, M.I., Laser and Their Applications IEEE London 1964, pp. 34–1, 34–2; Birnbaum, M. and Stocker, T.L., Brit. J. Appl. Phys. 17 (1966) 461; Birnbaum, M. and Stocker, T.L., IEEE J. Quant. Electr. QE-2 (1966) 184; Birnbaum, M. and Stocker, T.L., J. Appl. Phys. 39 (1968) 6032.
3. Sooy, W.R., Geller, M. and Bortfeld, D.P., Appl. Phys. Lett. 5 (1964) 54.
4. See [ 1] for biliographic list.
5. Bertolotti, M., de Pasquale, F., Marietti, P., Sette, D. and Vitali, G., J. Appl. Phys. 38 (1967) 4088.