激光原理第四章ppt課件(編輯修改稿)
2025-05-28 08:44 本頁面
【文章內(nèi)容簡(jiǎn)介】 pt s ptptPP P P PP??? ? ? ??s稱為斜率效率 結(jié)論：一旦激光器確定了，斜率效率就確定了；輸出功率隨泵浦功率線性增加。 上式對(duì)于放電激勵(lì)的氣體激光器例外 耦合系數(shù)： ?0=T0/2? 深圳大學(xué)電子科學(xué)與技術(shù)學(xué)院 ? The total loss encountered by the oscillating laser mode can conveniently be attributed to two different sources: (a) the inevitable residual loss due to absorption and scattering in the laser material and in the mirrors, as well as diffraction losses in the finite diameter reflectors。 (b) the (useful) loss due to coupling of output power through the partially transmissive reflector. It is obvious that loss (a) should be made as small as possible since it raise the oscillation threshold without contributing to the output power. 深圳大學(xué)電子科學(xué)與技術(shù)學(xué)院 The problem of the coupling loss (b), however, is more subtle. At zero coupling (that is, both mirrors have zero transmission) the threshold will be at its minimum value and the power emitted by the atoms will be maximum. But since none of this power is available as output, this is not a useful state of affairs. If on the other hand, we keep increasing the coupling loss, the increasing threshold pumping will at some point exceed the actual pumping level. When this happens, oscillation will cease and the power output will again be zero. Between these two extremes there exists an optimum value of coupling (that is, mirror transmission) at which the power output is a maximum. 深圳大學(xué)電子科學(xué)與技術(shù)學(xué)院 3）最佳透射率及功率 輸出功率和反射鏡的透射率 T有關(guān)。當(dāng) T增大時(shí)，一方面提高了透射光的比例，有利于提高輸出功率，同時(shí)又使閾值增加，從而導(dǎo)
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