ПРИМЕНЕНИЕ МЕТОДОВ ФЮХТБАУЭРА–ЛАДЕНБУРГА И СООТВЕТСТВИЯ ДЛЯ ОПРЕДЕЛЕНИЯ СПЕКТРОВ СЕЧЕНИЙ СТИМУЛИРОВАННОГО ИСПУСКАНИЯ НЕОДИМОВЫХ ЛАЗЕРНЫХ СРЕД

Rare-earth doped crystals with broad bands of gain spectra are attractive for femtosecond laser applications. Therefore, for this purposes crystals with disordered structure are of great interest. In this article we investigate laser-related spectroscopic properties of new trigonal crystals Nd3+:Ca10K(VO4 )7 (Nd:CKV), Nd3+:Ca9 La(VO4 )7 (Nd:CLaV) и Nd3+:Ca10Li(VO4 )7 (Nd:CLiV). The Füchtbauer-Ladenburg equation and the integral reciprocity method were applied for determination of stimulated emission cross section spectra for Nd3+ ions. The maximum values of emission cross sections and bandwidth (FWHM) near λ = 1,07 μm are 9,33·10 -20cm2 (σ – polarization, Nd:CKV) and 30 nm (π – polarization, Nd:CKV), near λ = 1,35 μm – 1,55·1020cm2 and 50 nm (π – polarization, Nd:CKV). The broad and smooth bands of the gain spectra in the regions near 1,07 and 1,35 μm make it possible to generate ultra short light pulses with duration of about 60 fs (1,07 µm) and 45 fs (1,35  µm) in the mode-locking regime. Для создания лазеров, генерирующих импульсы ультракороткой длительности, представляют большой интерес лазерные материалы с широкими полосами усиления. В этой связи значительный интерес представляют структурно разупорядоченные материалы, в частности новые кристаллические среды, принадлежащие тригональной сингонии Nd3+:Ca10K(VO4 )7 (Nd:CKV), Nd3+:Ca9 La(VO4 )7 (Nd:CLaV) и Nd3+:Ca10Li(VO4 )7 (Nd:CLiV). В данной работе формула Фюхтбауэра-Ладенбурга и интегральный метод соответствия применены для определения спектров сечений стимулированного испускания указанных выше кристаллов на переходах 4 F3/2 → 4 I9/2, 4 F3/2 → 4 I11/2, и 4 F3/2 → 4 I13/2 иона неодима. Максимальные пиковые значения сечений стимулированного испускания и наибольшие спектральные ширины полос в области 1,07 мкм составляют 9,33·10-20 см2 (σ-поляризация, Nd:CKV) и 30 нм (π-поляризация,  Nd:CKV), в области 1,35 мкм – 1,55·10-20 см2 и 50 нм (π-поляризация, Nd:CKV). Полосы стимулированного испускания, а следовательно, и усиления в областях спектра 1,07 и 1,35 мкм являются гладкими и бесструктурными с ширинами, позволяющими получать ультракороткие импульсы света с длительностью  ≈  60 фс (1,07 мкм), ≈ 45 фс (1,35 мкм) в лазерах на исследованных лазерных средах, работающих в режиме синхронизации мод.

APPLICATION OF FÜCHTBAUER–LADENBURG EQUATION AND RECIPROCITY METHOD FOR DETERMINATION OF EMISSION CROSS SECTIONS OF ND-DOPED LASER MEDIA

Rare-earth doped crystals with broad bands of gain spectra are attractive for femtosecond laser applications. Therefore, for this purposes crystals with disordered structure are of great interest. In this article we investigate laser-related spectroscopic properties of new trigonal crystals Nd3+:Ca10K(VO4 )7 (Nd:CKV), Nd3+:Ca9 La(VO4 )7 (Nd:CLaV) и Nd3+:Ca10Li(VO4 )7 (Nd:CLiV). The Füchtbauer-Ladenburg equation and the integral reciprocity method were applied for determination of stimulated emission cross section spectra for Nd3+ ions. The maximum values of emission cross sections and bandwidth (FWHM) near λ = 1,07 μm are 9,33·10 -20cm2 (σ – polarization, Nd:CKV) and 30 nm (π – polarization, Nd:CKV), near λ = 1,35 μm – 1,55·1020cm2 and 50 nm (π – polarization, Nd:CKV). The broad and smooth bands of the gain spectra in the regions near 1,07 and 1,35 μm make it possible to generate ultra short light pulses with duration of about 60 fs (1,07 µm) and 45 fs (1,35  µm) in the mode-locking regime

‘Superior to Disney’: colour animation at Lenfilm, 1936-41

This article examines the phenomenon of colour-film animation at Lenfilm during the period 1936–1941. It discusses the development of colour technologies at the studio during the 1930s and the ways in which its artists responded to the aesthetic challenge of colour. Three of the seven short films produced during this period have been selected as case studies; they are examined here in the context of filmed animations in the Soviet Union during the 1930s, in particular the debates prompted by the screening of three Disney animations in Technicolor at the Moscow International Film Festival in 1935. The formal analysis of the case studies is based on the digital restorations in recent years at the Russian State Film Archive (Gosfilmfond), but also the inspection of one nitrate-positive of Mstislav Pashchenko’s Dzhiabzha (1939), which has survived intact at the archive. The technical difficulties posed by the hydrotype process developed at Lenfilm, as well as the challenge of producing sufficient prints for mass distribution, also form part of the discussion