Laser reflection interferometry

The kinetics of the reaction has been studied by IR as well as laser reflection interferometry (LRI) [21,145]. The amount of polymer grown on the surface was measured from the LRI signal as a function of time. It was shown that propylene polymerization was about 30 times slower than ethylene polymerization [145]. hi addition, Kim et al. estimated the polymerization ac-... 

Catledge, S., Baker, R, Tarvin, J., and Vohra, Y., Multilayer nanocrystalline/microcrystalline diamond films studied by laser reflectance interferometry, in Diamond and Related Mater., 9 (8), 1512-1517 (2000). 

The nucleation of diamond and the successive growth can be monitored by laser reflection interferometry (LRI) [330, 331] using a setup shown in Figure 11.35. This method was first invented by K. Nishimura, and used for a NlRIM-type reactor. In this particular example, it is an ASTeX reactor that was used, but the method can be applied to any type of CVD reactors. 

The influence of the process parameters on BEN was studied in Ref. [331] using an ASTeX reactor. The substrate used was Si(lOO) of 1-inch in diameter, which was placed on a Mo substrate holder. No carburization was done before the BEN process. The microwave power was 900 W, and the substrate temperature was 725 °C. Laser reflection interferometry (LRI) [330, 331] was used to monitor the diamond nucleation and the subsequent growth rate. The biasing time was determined from the inflection point of the intensity of the LRI. At this point,... 

HOD Highly oriented diamond film invented by Stoner et al. [1], LRI Laser reflection interferometry. See Refs. [330, 331]. 

C. H. Wu, W. H. Weber, T. J. Potter, and M. A. Tamor, Laser reflective interferometry for in-situ monitoring of diamond film growth by chemical vapor deposition, J. Appl Phys., 73(6) 2977-2982 (1993)... 

Many researchers have performed various optical microscopic observations of the surface morphology of ice crystals, such as steps [10, 20-23], height topography [24-31], and QLLs [32, 33], by ordinary bright field microscopy [10, 23, 24], differential interference contrast microscopy [20-22, 25, 29-31, 33], two-beam interferometry [26-28], and laser reflection microscopy [32], However, no one has yet succeeded in proving, by their optical observations, that they could visuahze individual elementary steps, mainly due to the small height of elementary steps. 

The advent of lasers allowed optical interferometry to become a useful and accurate technique to determine surface motion in shocked materials. The two most commonly used interferometric systems are the VISAR (Barker and Hollenbach, 1972) and the Fabry-Perot velocity interferometer (Johnson and Burgess, 1968 Durand et al., 1977). Both systems produce interference fringe shifts which are proportional to the Doppler shift of the laser light reflected from the moving specimen surface. Both can accommodate a speci-... 

A more recent technique utilizes laser interferometry. Again we quote from Ref 7 With the interferometer, the movement of a reflecting surface can be monitored as a function of time. The surface can be a free surface or in transparent materials a reflecting plane within or... 

Laser interferometry employs the principle of optical interference to recover the sought acoustic information from the light reflected from, or scattered by, a surface under ultrasonic vibration. Its non-contact nature makes laser probing a preferred alternative to contact methods in studying surface waves, their diffraction and damping by intrinsically rough surfaces. 

Transition radiation is considerably weaker than Cerenkov radiation, however since it is a surface phenomenon it avoids problems with radiator thickness and reflections inherent to Cerenkov-generating silica plates. Optical TR can be measured using a streak camera. An optical TR system has been used to time-resolve the energy spread of an electron macropulse in a free-electron laser facility [10]. Interferometry of coherent, far-infrared TR has been used to measure picosecond electron pulse widths and detect satellite pulses at the UCLA Satumus photoinjector, using charges on the order of 100 pC [11],... 

The first use of laser interferometry in monitoring the dissolution rate of a resist during development was by Konnerth and Dill. " The basis of their idea is shown in Fig. 11.28. A laser beam is directed toward the film, which is immersed in the developer. The reflected beam from the surface of the film and that reflected from the interface between resist and substrate interfere constructively or... 

Figure 11.29 Reflectivity versus the time a resist film is immersed in a developer and monitored by laser interferometry during development. The film thickness versus time in developer (solid line) can be derived from the recorder trace as indicated in Eq. (11.27). (Reprinted with permission from American Chemical Society. )...

---