光(guang)電(dian)(dian)(dian)倍增(zeng)管(guan)是一(yi)個(ge)真空管(guan),其中(zhong)光(guang)電(dian)(dian)(dian)陰極(ji)吸收(shou)光(guang)產生自(zi)由電(dian)(dian)(dian)子,然后(hou)(hou)在(zai)高電(dian)(dian)(dian)壓(ya)(幾百伏)下(xia)被加速,在(zai)另一(yi)電(dian)(dian)(dian)極(ji)產生二(er)次(ci)電(dian)(dian)(dian)子,最后(hou)(hou)形成光(guang)電(dian)(dian)(dian)流(liu)(liu)。由于這一(yi)雪崩過程,光(guang)電(dian)(dian)(dian)流(liu)(liu)比光(guang)電(dian)(dian)(dian)二(er)極(ji)管(guan)中(zhong)的電(dian)(dian)(dian)流(liu)(liu)大好(hao)幾個(ge)數量級。因此,光(guang)電(dian)(dian)(dian)倍增(zeng)管(guan)可以用(yong)于單光(guang)子計數。光(guang)電(dian)(dian)(dian)倍增(zeng)管(guan)靈敏度(du)很高,帶寬很大(>1GHz),并且在(zai)很大動態范圍內具有很好(hao)的非線性。
光電倍增管的缺點在于尺(chi)寸(cun)大(與(yu)光電二極管相比),成本(ben)高(gao),需要高(gao)電壓,并且有些(xie)情(qing)況下量子效率(lv)較低(通常(chang)<25%,甚(shen)至有時<1%)。
一種尺(chi)寸很小的光(guang)電倍(bei)增管(guan)(guan)是微通道光(guang)電倍(bei)增管(guan)(guan),其(qi)中在摻雜(za)玻(bo)璃中具有單(dan)片的管(guan)(guan)子(zi)。由于尺(chi)寸很小,因此可(ke)以將多(duo)個通道集成一起形成二維的陣列(lie)來實現很大(da)的探測(ce)帶寬。
有(you)(you)些(xie)情況下,可(ke)以用(yong)雪(xue)崩二(er)極管(guan)代替光電(dian)倍(bei)增管(guan),前(qian)者(zhe)也是利(li)用(yong)了放大(da)(da)機制,但是放大(da)(da)發生在固(gu)態(tai)材料(liao)中(zhong),而(er)不是在真空管(guan)中(zhong)。采(cai)用(yong)包含(han)很多(duo)雪(xue)崩二(er)極管(guan)的(de)陣列可(ke)以得到很大(da)(da)的(de)有(you)(you)源區面積;這一器(qi)件有(you)(you)時(shi)被稱(cheng)為硅(gui)光電(dian)倍(bei)增管(guan)。與光電(dian)倍(bei)增管(guan)相比,硅(gui)光電(dian)倍(bei)增管(guan)更(geng)(geng)加便宜(yi),成(cheng)本(ben)更(geng)(geng)低,結構(gou)更(geng)(geng)穩固(gu)。并且通(tong)常(chang)具有(you)(you)更(geng)(geng)高的(de)量(liang)子效率,但是也具有(you)(you)更(geng)(geng)高的(de)放大(da)(da)噪聲。
還有一種混合光(guang)電(dian)(dian)倍增(zeng)管,其中(zhong)電(dian)(dian)子(zi)(zi)(zi)從一個光(guang)電(dian)(dian)極產(chan)生然(ran)后(hou)在幾千伏(fu)的(de)電(dian)(dian)壓下被加(jia)速(su)到半導體芯片(pian)上,它類似于雪崩(beng)(beng)二(er)極管。電(dian)(dian)子(zi)(zi)(zi)撞擊半導體會(hui)形(xing)成(cheng)電(dian)(dian)子(zi)(zi)(zi)轟擊增(zeng)益,然(ran)后(hou)形(xing)成(cheng)雪崩(beng)(beng)放(fang)大。這一器件與(yu)普通的(de)光(guang)電(dian)(dian)倍增(zeng)管速(su)度相似,并(bing)且脈沖振幅分辨率(lv)提高。并(bing)且,其響應(ying)時間(jian)很短,尺(chi)寸小。它們可應(ying)用在與(yu)光(guang)電(dian)(dian)倍增(zeng)管相似的(de)領域,包括光(guang)子(zi)(zi)(zi)計數。
在雪崩二極管(guan)中增(zeng)大有源區面積可以將多個(ge)像素點(dian)緊密排列在同一(yi)個(ge)芯(xin)片(pian)上來實現。這一(yi)器(qi)件有時也被(bei)稱為固態光電(dian)倍增(zeng)管(guan)或(huo)者硅(gui)光電(dian)倍增(zeng)管(guan)。
(來源:網絡(luo),版權歸(gui)原作者)