[Opt. Soc. America Technical Digest. Summaries of papers presented at the Conference on Lasers and Electro-Optics. Postconference Edition. CLEO '99. Conference on Lasers and Electro-Optics - Baltimore, MD, USA (23-28 May 1999)] Technical Digest. Summaries of papers presented at the Conference on Lasers and Electro-Optics. Postconference Edition. CLEO '99. Conference on Lasers and Electro-Optics (IEEE Cat. No.99CH37013) - 90° phase-matched THG of the CO/sub 2/ laser wavelength in AgGa/sub 1-x/In/sub x/Se/sub 2/