GT Advanced Technologies receives order for large optical sapphire blank for gravitational wave telescope

MERRIMACK, USA: GT Advanced Technologies Inc. announced that its subsidiary, GT Crystal Systems, has received an order for a large, low absorption, optical sapphire blank for the Large-Scale Cryogenic Gravitational Wave Telescope (LCGT) program located in Japan.

The LCGT will use the sapphire optic to measure changes in gravitational waves resulting from cosmic events. The LCGT is an extremely sensitive instrument that requires sapphire that contains an almost perfect crystalline structure, without bubbles or inclusions, throughout the optic. The sapphire must also be very low in optical absorption to prevent any heat from occurring, which can cause thermal expansion and hence thermal lensing.

GT Crystal Systems HEM sapphire has extremely low absorption properties at wavelengths of 1.064 um, which is significant because many future, high-power laser systems operate at this wavelength. GT HEM sapphire has been measured to have laser absorption values lower than 40ppm/cm at this wave length.

“The intrinsic sapphire quality required for the LCGT is very high and only the purest and most perfect sapphire can be used for this demanding application,” said Cheryl Diuguid, GT Advanced Technologies’ VP and GM of the Sapphire Equipment and Materials Group. “We are honored to have been selected for this exciting program. It is a true testament to the quality of the sapphire material we produce using our advanced sapphire furnace technology.”

The sapphire blank will be approximately ten inches in diameter and six inches thick. Delivery of the blank is scheduled for the early calendar 2012. GT’s HEM Sapphire was selected for the LCGT program as a result of past performance in other similar low absorption applications such as the Laser Interferometer Gravitational-Wave Observatory (LIGO) located in the United States.

Scientists are using gravitational wave telescopes to observe black holes and other objects in the distant Universe that cannot be observed with more traditional optical and radio telescopes. Gravitational waves are of interest to cosmologists as they may offer a possible way of observing the very early universe. Precise measurements of gravitational waves will also allow scientists to test Einstein’s general theory of relativity.