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Date: 9-3-2016
3341
Date: 28-1-2021
1133
Date: 22-12-2016
1382
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Sum- and Difference-Frequency Generation
Two waves of comparable intensity and frequency ω1 and ω2 are initially present, and a wave at the third frequency ω3 is created through the nonlinear interaction
P(ω3) = ∈0 χ(2)E(ω1)E(ω2), .........(1)
where ω3 = ω1+ω2. Similarly, a wave at the difference frequency ω3−ω2 = ω1 may be generated (ω3 > ω2 > ω1). A very common technique to produce the third harmonic of a neodymium laser is, first, the generation of the second harmonic and then sum frequency generation by mixing the second harmonic (ω2) with the unconverted portion of the fundamental beam (ω1).
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دراسة يابانية لتقليل مخاطر أمراض المواليد منخفضي الوزن
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اكتشاف أكبر مرجان في العالم قبالة سواحل جزر سليمان
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اتحاد كليات الطب الملكية البريطانية يشيد بالمستوى العلمي لطلبة جامعة العميد وبيئتها التعليمية
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