Narrow band laser source for efficient 3He polarization

Polarized 3He has been shown to be advantageous when used as an analyzer for polarized neutron scattering, an area of physics research that is growing quickly. The unique advantages of using polarized 3He as neutron spin filters, such as broadband and wide angular acceptance of neutron beams, have made it widely used in most neutron facilities. In order to polarize 3He gas, spin-exchange optical pumping scheme is used. It is based on excitation of alkali metal atoms by narrow-line laser radiation. Note, that working with different pressures of alkali atoms/buffer gas systems leads to variation of absorption line of atomic transition. Therefore, tunable linewidth of the laser source becomes essential. Finally, it is important to have wavelength tuning capability in order to reach the wavelength of atomic line. Commercially available laser systems don’t provide sufficiently narrow linewidth in order to match the absorption line of alkali metals such as Rb, K etc. Moreover no companies provide flexibility in wavelength and linewidth tunability. The overall objective of the current proposal is to develop narrowband high power laser system suitable for an effective 3He polarization and flexible for different experimental conditions such as type of buffer gas mixture, pressure etc. The laser performance will be checked in 3He polarization schemes and optimized toward highest polarization efficiency. The narrowband high power laser system will be developed at Optigrate Corp and will be tested on the off-situ and in-situ polarized 3He systems in Oak Ridge National Lab. The performance will be compared against current commercially available lasers in terms of pump up time, pump efficiency and saturation of 3He polarization. The laser neutron transmission measurement will be used to characterize the performance of the laser. Commercial application and other benefits. Development of the narrowband laser systems in the framework of current project has variety of other applications such as hyperpolarization of Rb with further momentum transfer to Xe atoms is used to increase sensitivity (up to 10000 times) of Magnetic Resonant Imaging. Optical magnetometer is based on excitation of Rb or K atoms with the same types of lasers and it leads to huge increase in sensitivity of magnetic field detection (on the order of femto-Tesla). High sensitivity dark matter detection is also based on excitation of alkali metal atoms. Finally, high power alkali metal lasers for defense application require narrow band high power pumping. With that being said, development of the narrowband laser system we propose covers many areas covering both commercial and Federal Government sectors and ranging from pure research (astrophysics) to medical, security and defense etc.