Laser thinning

The laser method is also the least expensive method yet developed for making thin superconducting films. Cost savings, then, may become more substantial later on, said Venkatesan, because the pulsed method lends itself to mass production. The lasers we ve been using are very low power, compared to what else is out there. With larger, more powerful lasers, thin films can be deposited over larger areas in even shorter amounts of time. ... 

Fig. J0.27 Excitation and electron injection from a dye into Ti02 particles (nanocrystalline layer) large arrows, excitation of the dye by a pump laser thin arrows correspond to an excitation within the conduction band by an additional light beam for probing the injected electrons...

Polyesters, such as PET are now widely used in the manufacture of fibers for textiles and other applications. While PET has many desirable properties that make it suitable for manufacturing fibers, there is a continuing need for polyester fibers that have improved properties, or properties that are different from PET, thereby opening new uses for polyester fibers. For example, PEN has found applications in high performance sailcloth materials or in industrial filtration applications. Micro fibers can be obtained from fibers using a laser thinning method. ... 

A. Suzuki and M. Tojyo. Poly(ethylene-2,6-naphthalate) microflber prepared by carbon dioxide laser-thinning method. Fur. Polym. J., 43(7) 2922-2927, July 2007. 

S. Nikumb, Q. Chen, C. Li, H. Reshef, H. Zheng, H. Qiu, and D. Low, Precision glass machining, drilling and profile cutting by short pulse lasers. Thin Solid Films, 477, 216—221, 2005. 

H. Monobe, K. Kiyohara, N. Terasawa, M. Heya, K. Awazu, Y. Shimizu, Infrared photoinduced alignment change for triphenylene-based columnar liquid crystals by using free electron laser. Thin Solid Films 438-439, 418-422 (2003)... 

P. (2010) Optical nonlinearities of Au/T102 films excited by high-repetition-rate femtosecond laser. Thin Solid Eilms,... 

Paul, A.J. Schenck, P.K. Bonnell, D.W. Hastie, J.W. "In Situ Monitoring and Model Simulations of BaTi03 Pulsed Laser Thin Film Deposition" In Film Synthesis and Growth Using Energetic Beams Atwater, H.A., Dickinson, J.T., Lowndes, D.H., Polman, A., Eds. MRS Symp. Series Vol. 388 Materials Research Society Pittsburgh, PA, 1996, 45-50. 

Imaging plates are exposed similar to radiographic films. They are read out by a LASER-scanner to a digital image without any developing process. After optical erasing of the virtual picture the same IP can be used cyclic up to more than 1000 times. The life time is limited by the mechanical stability of the IP s. An IP consists of a flexible polymer carrier which is coated with the sensitive layer. This layer is covered with a thin transparent protective foil. 

Figure C 1.5.13. Schematic diagram of an experimental set-up for imaging 3D single-molecule orientations. The excitation laser with either s- or p-polarization is reflected from the polymer/water boundary. Molecular fluorescence is imaged through an aberrating thin water layer, collected with an inverted microscope and imaged onto a CCD array. Aberrated and unaberrated emission patterns are observed for z- and xr-orientated molecules, respectively. Reprinted with pennission from Bartko and Dickson [148]. Copyright 1999 American Chemical Society.

In a heterostRieture laser, the aetive region ean be defined by epitaxial layers and made eonsiderably thinner. In GaAs/Al Ga. As heterostRietures, the aetive region ean be made as thin as 100 nm, and the threshold euRent... 

The requirements of thin-film ferroelectrics are stoichiometry, phase formation, crystallization, and microstmctural development for the various device appHcations. As of this writing multimagnetron sputtering (MMS) (56), multiion beam-reactive sputter (MIBERS) deposition (57), uv-excimer laser ablation (58), and electron cyclotron resonance (ECR) plasma-assisted growth (59) are the latest ferroelectric thin-film growth processes to satisfy the requirements. 

Nonmilitary infrared apphcations for germanium include CO2 lasers (qv), intmsion alarms, and pohce and border patrol surveillance devices. Germanium is used as a thin-film coating for infrared materials to decrease reflection losses or to provide heavy filtering action below 2 p.m. 

Writing by Bubble Forming. Bubble formation occurs under thin metal layers on polymeric substrate films, caused by local evaporation when hit by a focused laser beam (see Fig. 3c). Bubble formation occurs as in the DIP concept in dye-in-polymer films which are covered by a thin metal (mostiy gold) or ceramic layer (6) (see Fig. 3d). 

Deposition of Thin Films. Laser photochemical deposition has been extensively studied, especially with respect to fabrication of microelectronic stmctures (see Integrated circuits). This procedure could be used in integrated circuit fabrication for the direct generation of patterns. Laser-aided chemical vapor deposition, which can be used to deposit layers of semiconductors, metals, and insulators, could define the circuit features. The deposits can have dimensions in the micrometer regime and they can be produced in specific patterns. Laser chemical vapor deposition can use either of two approaches. 

I. W. Boyd, Laser Processing of Thin Films and Microstructures, Springer-Vedag, Berlin 1987. 

Epitaxial crystal growth methods such as molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD) have advanced to the point that active regions of essentially arbitrary thicknesses can be prepared (see Thin films, film deposition techniques). Most semiconductors used for lasers are cubic crystals where the lattice constant, the dimension of the cube, is equal to two atomic plane distances. When the thickness of this layer is reduced to dimensions on the order of 0.01 )J.m, between 20 and 30 atomic plane distances, quantum mechanics is needed for an accurate description of the confined carrier energies (11). Such layers are called quantum wells and the lasers containing such layers in their active regions are known as quantum well lasers (12). 

Pulsed Laser Evaporation. Laser evaporation or ablation consists of using a laser emitting at an appropriate wavelength, generally a KrF excimer laser, in a pulsed mode in a controlled atmosphere to deposit a thin film of a material the composition of which is that of the target (16—18) (see... 

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