哈工大 现代光学PPTModern Optics-Lasers.ppt

* Slide provided by Optics I student Kham Ho, 2004 * /~ypvsj/news/EtaCarinae.html P Cygni emission line profile of triply ionized carbon at 1548.2 ? in the central star of the cats eye planetary nebula, NGC 6543. Courtesy of the International Ultraviolet Explorer (IUE). Huggins and Miller were the first to observe the spectra of nova T Coronae Borealis, showing blue-shifted absorption line accompanying each emission line. The nova evolved and they later observed a spectrum characteristic of nebula. These P-Cygni lines are a characteristic common to all novae and stars with strong mass ejections or violent stellar winds such as Eta Carinae. The stellar ashes that accumulate often take the form of a circumstellar nebula of gas and dust. In the late 19th century, Keeler discovered the unusual emission lines of P-Cygni, a variable star which may have had a novae phase in 1600. It had several bright lines ascribed to helium, and is now classified as a very slow nova. A quote from C.S.Beals paper on the interpretation of these stars: Both P-Cygni and Eta Carinae have been numbered among the novae ... This similarity with novae, considered in connection with the absorption on the violet edges of emission lines and the variation in the width of P Cygni lines with wavelength, suggest that the peculiarities in the spectra of these stars is due to the ejection of of gaseous material in a manner similar to that suggested for Wolf-Rayet stars. * Slide provided by Optics I student Kham Ho, 2004 Microstructure of Nd:YAG ceramics YAG Ceramics vs YAG Single Crystals * YAG Ceramics vs YAG Single Crystals * YAG Ceramics vs YAG Single Crystals EO Ceramics Gain Medium-PLZT (Lanthanum-Modified Lead Zirconate Titanate) Absorbance and Photoluminescence of RE doped PLZT ceramics Nd3+ Ion in PLZT Host Nd3+ Doping Photoluminescence Spectra of Nd:PLZT Nd:PLZT Absorption Spectrum 1.0 at.% Nd:OC 0.5 at.% Nd:OC Upper Energy Level Lifetime Absorption of Tm:PLZT and Ho-Tm:PLZT Ho and Tm c