Sapphire plates

Materials. PVCz (Takasago International Co. Ltd.) was purified by several reprecipitations froa benzene-methanol solution. 1-Ethylpyrene (EPy) was recrystallized and sublined in vacuo before use. PMMA was reprecipitated twice froa tetrahydrofuran solution with nethanol. PVCz films were prepared by spin-coating a 10 wtX anisole solution of the polyner on a quartz plate. PMMA and EPy were dissolved in chlorobenzene and cast on quartz or sapphire plates. 

Fig. 1. Schematic of experimental setup. %J2 - 800 nm wave-plate SP 2-mm sapphire plate PI, 2 45° quartz prisms P3 69° quartz prism, the distance from P3 to the NOPA crystal is 80 cm CM1, 2 ultrabroadband chirped mirrors GR 300 lines/mm ruled diffraction grating (Jobin Yvon) SM spherical mirror, R=-400 mm BS1, 2 chromium-coated d=0.5 mm quartz beam splitters. SHG crystal 0.4-mm 0=29° BBO (EKSMA) NOPA crystal 1-mm 0=31.5° BBO (Casix) SHG FROG crystal 0=29° BBO wedge plate d=5- -20 pm (EKSMA). Spherical mirrors around NOPA crystal are R=-200 mm Thick arrows on the left indicate the data flow from the pulse diagnostic setup (SHG FROG) and the feedback to the flexible mirror.

The SFA consists of a hermetically closed stainless steel chamber that can be filled with any transparent liquid or gas of choice. Mica is a preferred substrate in the SFA, though other surfaces, such as single-crystal sapphire plates have also been used [10]. In the SFA, the force acting between the surfaces, mounted in a crossed cylinder configuration, as a function of surface separation is measured. The data obtained are normally plotted as force, FC(D), normalised by the undeformed geometric mean radius of the surfaces, R This quantity is related to the free energy of interaction per unit area, G, between two flat surfaces at the same separation [11] ... 

The experimental details have been reported elsewhere (X, X) Briefly, matrices are formed by codeposition of excess argon with atomic potassium on a sapphire plate mounted inside an ESR cavity which is itself attached to a variable temperature liquid helium dewar. Cluster formation occurs during deposition and is accomplished by warming the sapphire surface above a nominal deposition temperature of 4.2 K. For spectra shown here, temperature measurements were made with a calibrated carbon resistor and are judged accurate to within 5%. 

Figure 4 Typical cryostat design for solution and powder samples. This design features an expanded berylhiun dome, which allows detection of the transmitted beam as well as the emitted X-rays that contribute to the NRVS signal. The Be dome and a thin polyethylene window on the front face of the sample cell minimize the absorption at 6.4 and 14.4 kev. A sapphire plate provides excellent thermal contact between the sample cell and the cryostat cold head, as well as allowing optical access for off-line Raman measurements to monitor sample integrity. Sample temperatures in the 20 - 30 K range are typically achieved for both solutions and powders...

Essentially, a small part of the laser pulse train that is ultimately used to trigger the photocathode is split off to create a synchronized laser probe pulse train. The probe line is equipped with different nonlinear optical devices that permit the tunability of the probe beam from the near UV to the NIR. Available probe sources include the laser fundamental (790 nm) and second harmonic (395 nm), a white-light continuum (470-750 nm) generated in a sapphire plate, and a continuously tunable Optical Parametric Amplifier (470-750 nm, 1000-1600 nm, and 240-375 nm by SHG), able to deliver light pulses shorter than 30 fs after compression. 

Previte, M. J., Zhang, Y., Aslan, K., and Geddes, C. D. (2007). Real-time Thermal Im ng of Microwave Accelerated Metal-Enhanced Fluorescence (MAMEF) Based Assays on Sapphire Plates Journal of fluorescence 17 639-642. 

A fraction of the amplifier output light (800 nm) is split from the main beam for continuum generation prior to harmonic generation. This is accomplished by the red light (a few tens of pJ) being focused into a 1-mm thick sapphire plate where, at... 

A molybdenum die is normally used for sapphire growth and rhenium for spinel, MgAl204. Sapphire plates are grown over 15 cm in width, and many small ribbons can be produced simultaneously from a single furnace. ... 

Depth-distribution of fluorescent dyes in silk fabrics (6) Silk woven fabrics were dyed with carthamin according to the literature and pressed firmly to the sapphire plate. The fabric consists of a lot of fibers, so that some of them are excited under the TIR condition and others under the normal one. Their relative contributions are changed with the incident angle. 

Although the contact between the sapphire plate and silk fabrics is not good, the difference in fluorescence spectra under TIR and normal conditions was observed. This promises that the present spectroscopy is useful even for materials with optically... 

Figure 15-13. Sources of infrared radiation emitted from a system composed of an oil film between a sapphire plate and a steel ball.

A small fraction of the pump beam generates a broad spectral continuum in a sapphire plate. The larger fraction is frequency doubled and sent by beam splitters into three BBO crystals for parametric amplification. The seed beam collimated from the focal spot in the sapphire plate is also imaged into the three BBO crystals, where they are superimposed on the frequency-doubled pump beams. The three parametric amplifiers can be independently tuned by changing the orientations of the crystals. The total tuning range is only limited by the spectral bandwidth of the seed beam continuum. 

Chapman and co-workers have reported the direct spectroscopic observation of benzocyclobutadiene itself by reaction of cis-1,2-di-iodobenzocyclobutene with zinc powder at 230 °C. Initial cooling of the resultant vapour deposited a mixture of dimeric material and traws-l,2-di iodobenzocyclobutene. The benzocyclobutadiene was trapped in an argon matrix at 20 K on either a caesium iodide or a sapphire plate for spectroscopic examination. The infrared spectrum showed a band at 700 cm which is probably due to one of the C—H bond deformations of the four-membered ring. The ultraviolet spectrum showed at 243, 246.5,256, 270, 281.5, and 289 nm. On warming above 75 K, the known benzocyclobutadiene dimer (150) was formed and identified by comparison with authentic material. 

A thermocouple is inserted into a dummy sample, which is located symmetrically with the sample on the hot stage. The temperature of the hot stage is kept constant and the phase shifts are measured as a function of frequency for the determination of exact thermal diffusivity. In the case of TWA, the temperature is scanned at a constant rate from 0.1 to 10 K min". A thin synthetic sapphire plate is used as a reference material to check the thermal diffusivity value. 

Figure 2.30 shows the a value of a synthetic sapphire plate as a function of temperature, which indicates a monotonic decrease with increase in temperature. The value of at 25 C is in good agreement with the literature values. It is confirmed that the time constant of the sensor or total measurement system is adequate in the experimental frequency range up to 2 kHz. 

Liquid samples are contained between thin (150 /rm) sapphire plates. The thickness of the sample film depends on the material being studied. For measurements on liquid mercury, films of 15 /cm were used for selenium, a lighter element, 230 /cm films could be used. In general, Bragg diffraction of x-rays from the crystalline sapphire cell windows can be expected to interfere with the beam di acted from the liquid sample. This can be avoided if, in the construction of the cells, the sapphire plates are oriented such that no Laue diffraction spots appear in the horizontal scattering pleme. Although other corrections such as for... 

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