1. Two-photon absorption inside BBO crystal during UV nonlinear optical conversion (PDF file here)
2. Multicrystal harmonic generator compensates for thermally induced phase mismatch (PDF file here)
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Our latest result on the 2-photon absorption and the subsequent heating of the nonlinear optical crystals are presented in the following 2 papers that will be presented at Photonics West 2000 (LASE200), 3928-28 & 3928-29
1. Two-photon absorption inside BBO crystal during UV nonlinear optical conversion (PDF file here)
2. Multicrystal harmonic generator compensates for thermally induced phase mismatch (PDF file here)
.
Conclusion:
2-Photon absorption is the key factor in limiting the conversion effciency during nonlineat optical conversion, especially when the absorption is not symmetrical.The current available data on absorption cross section and heat conductivity limit our ability to very accurately model the thermal profile generated. But, the qualitative and quasi-quantitative theoretical modeling is consistent with what we have observed.
(Background: conversion efficiency decreases
as the average power increases)
