——換個(gè)視角看光學(xué)發(fā)展(編輯修改稿)
2025-02-23 19:34 本頁面
【文章內(nèi)容簡(jiǎn)介】 有關(guān)的。其中，有關(guān)微觀粒子的光譜或能譜等方面的研究占了很大的比例。 ? 總的來說，對(duì)光的量子性的研究使人們對(duì)光的本性的認(rèn)識(shí)產(chǎn)生了質(zhì)的飛躍。同時(shí)還可以看出，相干性是量子性的重要基礎(chǔ)。量子性是人們對(duì)光的本質(zhì)在更高層次上的認(rèn)識(shí)，是光學(xué)發(fā)展的必然結(jié)果。 “激光冷卻” —— 頗具代表性的創(chuàng)新 ? 激光冷卻在光與物質(zhì)的相互作用中，充分利用了光的量子性（光子與被冷卻粒子所構(gòu)成系統(tǒng)的動(dòng)量守恒） ? 同時(shí)又巧妙地利用了光的相干性（例如：在Sysiphus Cooling中，利用兩束相反方向傳播的圓偏振光的相干疊加來獲得光學(xué)周期勢(shì)）。 ? 激光冷卻技術(shù)的發(fā)明直接導(dǎo)致了玻色 愛因斯坦凝聚這一著名理論論斷的實(shí)驗(yàn)驗(yàn)證（ 2023年獲獎(jiǎng)），這成為 20世紀(jì)末物理學(xué)的重大突破之一 ? This mechanical action of light is used in laser cooling and trapping to reduce the velocity spread for a collection of atoms (cooling), or to confine the atoms in a small volume (trapping). ? To achieve trapping, the light must induce a positiondependent force on the atoms (in contrast to cooling which requires a velocitydependent force). Different types of atom trap have been designed. The most often used is the MagoOptical Trap (MOT). In a MOT, trapping is acplished with three pairs of counterpropagating laser beams and an inhomogeneous magic field. ? A collection of sodium atoms (yellow dot in middle of picture) trapped in a MOT. ?Deceleration of Atoms ?Light acts mechanically on material objects, which means it can change their positions and velocities. MOT Timeofflight method ? The six laser beams are switched off. The atom cloud expands in a way determined by its temperature, at the same time as the atoms fall. They fall through a sheet of laser light and the resulting fluorescence is recorded. Since the atom cloud has expanded the signal has a temporal spread. By measuring thi
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