Ib. Zotova et Yj. Ding, Optical parametric oscillators in the presence of strong two-photon absorption for extended applications of nonlinear optical materials, OPT COMMUN, 198(4-6), 2001, pp. 453-458
We show that two-photon absorption (TPA) strongly affects backward and forw
ard optical parametric oscillation (OPO) in certain wavelength ranges. Afte
r introducing a normalized coefficient of TPA, we have obtained a simple ex
pression for the threshold intensities in the presence of TPA, that is the
same for both configurations of OPO. The threshold intensities increase as
the TPA coefficient increases. At the same time, the conversion efficiencie
s decrease. We have shown that even if the threshold intensity is just incr
eased by a very small factor due to TPA the conversion efficiency can be re
duced considerably. We have considered several nonlinear optical materials
as examples to illustrate the trade-off among different parameters such as
the TPA coefficient vs. pump wavelength, and, the pulse energy density vs.
crystal length. Our results are important for implementing optical parametr
ic oscillators in the extended wavelength ranges, such as visible, mid-IR,
far-IR, mm and THz. (C) 2001 Elsevier Science B.V. Alt rights reserved.