​Application of Sapphire Crystal in Optical Field

Application of Sapphire Crystal in Optical Field

Different qualities of sapphire are used in optics. The most recognized classifications of sapphire optical quality are listed in the appendix.

Sapphire portholes with diameters from a few millimeters to hundreds of millimeters are used in a variety of installations on the ground, underwater and in outer space, and withstand a wide range of temperatures and pressures - from low to high temperatures. Figure 1.31 shows an example of a sealed window design. It is used in environments with high pressure both inside and out, starting from low temperature to 720K.

Sapphire portholes are used in gas cryostats and helium microscope stages, with a diameter of D(12...25) x 2 mm sealed on metal flanges or fitted with sealing rings in the grooves of the device. Copper gaskets and indium wires provide a vacuum seal for the cryostat.

As described in the book Superconductivity at Oxford Instruments; the positions occupied by sapphire portholes can be seen in the diagram of Figure 1.32 compared to those made of other materials. The diagram allows the selection of porthole materials that meet the stated working conditions. Sapphire is now also used in the scan windows of cash registers to read barcodes.

Portholes with 1° and 3° wedges are used in laser engineering (Fig. 1.33) as partial mirrors or rhomboids to control the laser beam.

Sapphire can be used as an energy recovery window. One of the factors limiting energy recovery from the device is that the secondary electron resonant discharge in vacuum is proportional to the secondary electron emission coefficient (Table 1.1). As can be seen from this table, this performance of sapphire compares to other dielectrics.

Sapphire lenses and diamond mirrors are used in extremely harsh conditions, in environments that glass similar products cannot tolerate, or where the high refractive index properties of sapphire are required.

The sapphire optical fiber is integrated in the continuous temperature control device to obtain the most unbiased data on the melting state of the relevant melting furnaces, blending furnaces and mixing furnaces. They can work in molten or alloyed molten steel or in highly corrosive solutions. Sapphire is the only existing optical material that retains its optical properties and ability to operate in cast iron and steel melts. The optical fiber is introduced through the lining so that one end is placed in the melt and the other end is outside the lining. The luminous intensity of the optical fiber is proportional to the temperature of the melt. The thermal emission is converted into a signal for an automated temperature control system by a pyrometer transducer. To increase the strength of the sapphire rod, fix it in a ceramic tube with a high temperature ceramic composite, and install the final ceramic rod into the furnace lining. [13,14]

The optical fibers integrated into the bar stock work throughout the process cycle until the lining is replaced. In molten gold, a 4mm diameter sapphire optical fiber can be subjected to heating to 2,070K and subsequent cooling at 2 degrees per second.

Naturally, the lowest loss of light absorption and scattering is characteristic of colorless sapphire. However, the optical flow coming out of the metallurgical furnace is so intense that it does not need to be economized. The use of colorless sapphire optical fiber and the ruby tip and end are protruded into the frit to improve measurement accuracy. The intensity of transmitted light is proportional to temperature, but additional measurement of chromium luminous intensity is required for clarification.

Sapphire fibers are also classified as optical fibers. When the fiber is grown along the C-axis, the propagation of light is independent of polarization. However, this system device was developed by the Single Crystal Research Institute in cooperation with the Foundry Institute. The measurement range is 720K-2070K, and the indication error is 1%.

Kunshan Shuojing Optoelectronics Technology Co., Ltd. is involved in a wide range of new materials, and has complete preparation methods and means for functional ceramics and sapphire crystals, scintillation crystals, and laser crystals, forming optically transparent ceramics, sapphire optical windows, scintillation crystals, lasers and nonlinear crystals The main four series of high-tech products.