Mid-infrared radiation in the 5–18-μm range has been obtained by difference frequency generation in a AgGaSe2 crystal by pumping with the output of a type I LiNbO3 optical parametric oscillator (OPO). Here we suggest the use of a LiTaO3 retarder to achieve an orthogonal state of polarization between OPO outputs that are necessary for efficient pumping of a AgGaSe2 crystal. Several tens of kilowatts of peak power near 8 μm and continuously tunable operation in the above range have been obtained.
© 1998 Optical Society of America
Original Manuscript: May 21, 1997
Revised Manuscript: October 14, 1997
Published: March 20, 1998
Kazi Sarwar Abedin, Sajjad Haidar, Yuji Konno, Choichi Takyu, and Hiromasa Ito, "Difference frequency generation of 5–18 μm in a AgGaSe2 crystal," Appl. Opt. 37, 1642-1646 (1998)