Third harmonic generation of CO₂ laser radiation AgGaSe₂ crystal

GOPAL C BHAR, PATHIK KUMBHAKAR¹, D V SATYANARAYANA², N S N BANERJEE²,

U NUNDY² and C G CHAO³

Laser Laboratory, Physics Department, Burdwan University, Burdwan 713 104, India

¹ Present address: Physics Department, Regional Engineering College, Durgapur 713 209, India

² Centre for Advanced Technology, Indore 452 013, India

³ Anhui Institute of Optics and Fine Mechanics, China

Email: buphygcb@dte.vsnl.net.in

Abstract.

Generation of third harmonic of CO₂ laser radiation has been obtained in a type-II, q =57^o cut 9 mm thick AgGaSe₂ crystal for the first time by sum-frequency-mixing of the fundamental with its second harmonic, the latter being obtained using another type-I, q = 55^o cut 11 mm thick AgGaSe₂ crystal. The energy conversion efficiencies obtained for second harmonic and third harmonic generations are 6.3% and 2.4% respectively with the input fundamental pump power density of 5.9 MW/cm² only. The wavelength of the fundamental CO₂ laser radiation used for the generation of harmonics is 10.6 mm, P(20) line. A compact TEA CO₂ laser source has been built in the laboratory.

Keywords: Nonlinear optical material; third harmonic generation; AgGaSe₂ crystal.

Pacs No. 42.65.Ky; 42.70.Mp; 42.70.Nq