An Ultra-Sensitive and Compact Superluminal Ring Laser Gyroscope
Abstract
Recently, we have shown that the fast light effect and its manifestation in the white light cavity effect can be used to realize a superluminal ring laser gyroscope (SRLG) that can be ~10^6 times more sensitive when compared to a conventional ring laser gyroscope (RLG) of the same size. Alternatively, for a given accuracy need, the SRLG can be much smaller in size than a conventional RLG, since the sensitivity of such a gyroscope scales with the enclosed area. A simple modification of the SRLG can turn it into a superluminal ring laser accelerometer, with the same degree (10^6) of enhancement in sensitivity compared to a conventional interferometric accelerometer, with no direct dependence on area. With enough resources devoted to miniaturization, it should be possible to use this technology to realize a three-axes superluminal inertial measurement unit (SIMU) that will occupy a volume of about 1.65 cubic inches (3 cm X 3 cm X 3 cm), with a gyro sensitivity of ~1.6X10^(-7) deg/hr/root-Hz, and an acceleration sensitivity of ~3 pico-g/root-Hz. In 2012, the superluminal gyroscope was selected as a game changing technology by NASA. The goal of this seed project would be to carry out a key experiment that would establish the feasibility of realizing this technology, focusing only on the SRLG. So far, we have realized a superluminal ring laser (SRL) using a pair of Rb vapor cells, one of which is loaded with a high pressure Ethane buffer gas, and the other contains a single isotope of Rb. This approach entails serious mode competition that does not allow simultaneous lasing in both directions, thus preventing the demonstration of a gyroscope. Under this seed project, we will use a simpler approach to demonstrate operation of a pair of superluminal ring lasers that are counter-propagating and spatially overlapping, each using a simple, single vapor cell containing two isotopes of Rb, without causing mode competition. For the laser in each direction, we will use a single Rb cell, containing two isotopes in a natural mix. One isotope (Rb-85) will be used to produce a relatively broad band Raman gain, while the other isotope (Rb-87) will be used to produce a very narrow band Raman depletion. The differences in the transition frequencies within these isotopes make this possible. The cell that produces gain and depletion in one direction will not affect the gain or depletion of the laser in the other direction, because the Raman-gain/depletion occurs for co-propagating pumps only. The proposed experiment will be carried out in two stages, over 12 months. During the first six months, we will demonstrate a unidirectional superluminal laser in a monolithic cavity. During the second six months, we will demonstrate and SRLG using two such laser in counter-propagating and overlapping modes. The fund requested will be used to support a graduate student and 50% effort of a post-doctoral associate, as well as to obtain some of the parts (such as DBR lasers and offset-phase locking systems) for carrying out the proposed work.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 24, 2019
- Source ID
- W911NF1510643
Entities
People
- Mohamd Selim Shahriar
Organizations
- Army Contracting Command
- Defense Advanced Research Projects Agency
- Northwestern University