- Chuydn miic cua cac didn tir miic donor xudng xoing hda tri, biic xa cac photon vdi nang lugng: hv2 = Eg Ê
d. Cac ket qua do pho huynh quang va tan xa Raman
Chiing tdi da tien hanh mot sd phep do pho de xac dinh che do hoat dgng va can chinh he do, vi du nhu pho huynh quang cua ZnS pha tap Mn ( hinh 24), pho tan xa Raman ciia cac hydrocarbon thdng thudng kfch thfch bing laser Argon va laser He-Nẹ Cac phep do cho thay he do phd mdi dat dugc do nhay va do phan giai cao, cd nhidu tid'n bg trong vide thuc hien cac phep do pho huynh quang va Raman.
Chiing tdi da thanh cdng trong viec thu pho tan xa Raman cua cac chiet phan diu md kfch thfch bing laser He-Ne 30mW. Do nhay cao cua he trong vimg đ va vung hdng ngoai dem lai kha nang nghidn ciiu pho Raman cudng do kfch thich yeu, sir dung cac laser He-Ne cdng suit trung binh thay cho laser Argon cdng suit Idn lam lanh bing nude, dieu nay giiip cho vide nghidn ciiu quang pho Raman didn ra don gian va tiet kiem. Hon nua, vide sir dung cac ngudn kich budc sdng dai nhu laser He-Ne de nghidn ciiu Raman giiip tranh dugc cac dam phd huynh quang thudng gap phai khi sir dung cac ngudn kfch budc sdng ngin cdng suat cao nhu laser Argon. Cac phep do dugc tid'n hanh cho thay khdng cd su xuat hien cua dam pho huynh quang trong phd Raman khi thfch thfch bing budc sdng 632,8nm cua laser He-Nẹ Khi kich thfch bing laser Argon gin xiing tir ngoai cd the tao ra pho huynh quang chdng Idn phd tan xa Raman. Dieu nay dugc the hien rd rang khi nghidn ciiu tan xa Raman cua cac miu dau md 5B110 va 5B115 (chiet phim diu khai thac tir md Bach Ho, Viet Nam). Phd tan xa Raman kfch thfch bing laser He-Ne xuat hien nhieu dinh Raman hon, cho nhidu thdng tin hon ve miu vat, so vdi trudng hgp kfch thich bing laser Argon (hinh 17).
t.OiJO irr: 1,5 t- l.O I / / tOC-0 ifOG - * » t i — J
frbOb »>0& 1OO0C
i:*oo iioob
Hinh 17 : pho tan xa Raman ciia cac miu dau md Bach Ho Viet Nam ạ Miu 5B110 kfch thfch bing laser argon
b. Miu 5B110 kfch thfch bing laser He- Ne c. Miu 5B115 kfch thfch bing laser argon d. Miu 5B115 kfch thfch bing laser He- Ne
ẹ Ket luan
Tir mot may ghi pho each tir kep GDM - 1000 (Carl Zeis, Jena, CHDC Diic) chiing tdi da nang cap tang do nhay cung vdi x^ung quet pho rdng hon (400-900nm) va chuyen đi thanh cdng thanh mdt he do pho phan giai cao kdt ndi may tfnh sir dung ky thuat lock-in. Day la mot giai phap kinh te, rat phu hgp cho cdng vide nghien ciiu va dao tao trong trudng dai hgc. He quang pho mdi nang cap cd the thu dugc cac tfn hieu quang yd'u, nhu phd tan xa Raman ciia cac miu dau md Viet Xam kfch thfch bing laser He-Ne 30mW thay vi phai sir dung laser Argon nhu trudc daỵ Pho Raman kfch thfch bing laser He- Ne cd rat nhieu Igi the so \di kfch thfch bing laser .Argon . Cac kd't qua budc dau hiia hen kha nang sir dung he thu phd nay trong cac nghidn ciiu tinh chat cua vat lieu bing hieu irng quang phi tuyd'n trong tuong lai