Sapphire transmittance

The entrance window is a relevant part of the sensor. Common glasses as well as most transparent plastics block UV radiation. Standard UV-transmitting materials like quartz and sapphire are expensive. For UVA and to some extent the UVB special glasses but also plastics like some PMMA-derivatives or some silicon gels are available with a reasonable transmittance down to about 330 nm. For UVC applications with the important 254 nm line of Hg, quartz remains the standard solution. 

The fabrication process of vanadium oxide (VO2) has also been studied using RBS/C. Since optieal and electrical properties of VO2 are dramatically changed at 68°C due to phase transition, VO2 is regarded as one of the candidates for thermally activated electronic or optical switching devices for optieal fibers or sensors. To obtain the desired properties, the development of the fabrication process for very thin films, without crystalline defects on various substrates, is required. Single-crystalline VO2 thin films on (0001) plane of a sapphire substrate have been synthesized by a laser ablation method. The quality of VO2 was examined by X-ray diffraction and RBS/C method. The eleetrieal resistanee and the optical transmittance of the VO2 film were measured under inereasing and deereasing temperatures. At a temperature of 68 °C, an abrupt transition of resistanee from metal to... 

PCA ceramics with submicron grain size and high in-line transmittance have found applications in metal halide lamps [18]. The in-line transmittance in the visible range could reach >70 % of that of sapphire, which is almost the theoretical limit for alumina ceramics with that range of grain sizes [19]. In addition, mechanical... 

Optical material Transmittance range (nm) Refractive index at 600 nm Relative rupture strength (sapphire = 100)... 

The signal generated by the camera when a sapphire column flushed with nitrogen is placed in between the IR source and the camera, is indicated with DLq. When CO2 is fed into the column, it absorbs part of the radiation and the remaining signal transmitted to the camera is denoted with DL. From these two signals, the transmittance and absorbance can be defined as follows ... 

Mediate volume transmitter. Stainless steel turbine in sapphire cups. Hall sensor... 

The temperature dependences of the electrical conductivity and of the thermoelectric power of boron films deposited on sapphire substrates have been measured. The energy band gap and optical constant (n, k) of boron have been estimated from the results for optical transmittance and reflectance in the visible and infrared spectral regions. 

Transmission and reflection spectra of the boron films on sapphire were measured over a wavelength range 200-2500 pm using an MPS-50 (Shimazu) spectrophotometer. In the transmission and reflection measurements, an uncoated sapphire and an evaporated aluminum film were used as the references, respectively. Absorption coefficient, refractive index, and extinction coefficient of the boron films were calculated from the measured transmittance and reflectance at normal incidence. 

Figure 21.10 The hght transmittance of three aluminum oxide specimens. From left to right single-crystal material (sapphire), which is transparent a polycrystaUine and fully dense (nonporous) material, which is translucent and a polycrystaUine material that contains approximately 5% porosity, which is opaque. (Specimen preparation, P. A. Lessing.)...

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