National Technology & Engineering Solutions of Sandia, LLC

Jongmin Lee

Grant Biedermann

Christopher Todd DeRose

Michael Gehl

Charles A Walker

Peter Schwindt

Yuan-Yu Jau

Anthony L Lentine

Daniel Beom Soo Soh

David Bossert

Hayden James Evans McGuinness

Aaron M Ison

Daniel Paul Gillund

Jonathan David Sterk

Dennis J De Smet

Peter D D Schwindt

Kevin Michael Fortier

Adrian Samuel Orozco

Weng W Chow

Shanalyn A Kemme

Kyle H Fuerschbach

A compact grating-mirror magneto-optical trap (GMOT) cold atom inertial sensor head is disclosed. To make the sensor head compatible with the high vibration levels encountered in dynamic environments, the number of optical ports in the vacuum chamber is minimized and various components, including fixed optical components and a reflective grating chip, are hard mounted within the vacuum chamber. The use of the reflective grating chip reduces the number of optical ports required for cooling beams from six to one. The number of optical ports is further reduced by time multiplexing multiple beams passing through a given optical port.

Compact grating magneto-optical trap sensor head for inertial navigation in dynamic environments

Various optical systems for use in a light pulse atomic interferometer (LPAI)-based one-, two-, or three-axis accelerometer or gyroscope are disclosed. As an LPAI accelerometer or gyroscope may employ many different laser beams to implement the LPAI functionality, ways of combining these different laser beams to thereby simplify the optical systems are desired. The cooling laser beam portion of the optical system may be simplified using one or more reflective grating chips. The Raman laser beam optics may be simplified using combiners and separators. For LPAI systems sensing along three axes, various optical switching schemes may be employed, including ones that generate variable data-rates with a primary sensing axis having a higher data-rate than the secondary sensing axes. Further, by combining various laser beams in a time-multiplexed manner, the number of optical fiber tethers to a sensor head may be reduced.

Compact atom interferometry inertial navigation sensors with tailored diffractive optics

A large-dynamic and high-sensitive measurement protocol of an evanescent-field-mode guided atom interferometer accelerometer is disclosed. Cold atoms of a finite temperature are one-dimensionally guided in an evanescent field optical dipole trap. The first-step pathfinder protocol employs the revival of atomic coherence, i.e., the recovery of atomic fringe visibility to capture global interferometric signature to provide the information (e.g., a large-range of approximate acceleration sensing) to optimize the physical parameters for the second-step high-precision guided LPAI measurement. The contrast of atomic fringe visibility returns to unity given a specific interrogation time during the pulse sequence. To ensure the optimal interrogation time, the method employs a time-scanning sequence about the anticipated optimal interrogation time. The anticipated optimal interrogation time is determined via a conventional inertial measurement unit co-sensor or through the use of a look-up table. The method may alternatively employ a phase-scanning sequence.

Measurement protocol for large dynamic range and high sensitivity of an evanescent-field-mode guided atom interferometer

A hybrid inertial navigation system and method are provided. The system includes a conventional inertial measurement unit (with a three-axis accelerometer and a three-axis gyroscope operating at a high data rate and low sensitivity), light pulse atom interferometer accelerometer and gyroscope (operating at a low data rate and high sensitivity), and a processing system. The method of the hybrid inertial navigation system includes precisely determining an acceleration and an angular velocity and allowing light pulse atom interferometry operation under dynamic environments. A processing system of the hybrid inertial navigation system performs feedforward correction operations on the light-pulse atom interferometer accelerometer and gyroscope of the hybrid inertial navigation system. The processing system determines one or more control signals based on the inertial information from the conventional inertial measurement unit, a light pulse atom interferometer model, and the feedforward algorithm.

Hybrid inertial navigation system and method

A guided cold-atom inertial sensor system comprises an atom trap integrated platform, a laser system, a magnetic field system, a control system, and a computing system. The laser system and magnetic field system are adapted to form a magneto-optical trap (MOT) about a suspended waveguide of the atom trap integrated platform made of membrane integrated photonics. After loading cold atoms from a MOT, the photonic atom trap integrated platform generates one-dimensional guided atoms with an evanescent field optical dipole trap (EF-ODT) along the optical waveguide to create guided atomic accelerometers/gyroscopes. Motion of atomic wavepackets in a superposition state is created along the guided atom geometry by way of state-dependent momentum kicks. The light-pulse sequence of guided atom interferometry splits, redirects, and recombines atomic wavepackets, which allows measurement of atom interference fringes sensitive to inertial forces via a probe laser.

Guided cold atom inertial sensors with membrane integrated photonics on atom trap integrated platforms

An atom trap integrated platform (ATIP) comprises a substrate, a membrane, and a suspended waveguide. The substrate has an opening formed therein. The membrane extends across a portion of the substrate opening. The suspended waveguide is formed on the membrane such that the suspended waveguide extends from a first edge of the substrate to a second edge. A magneto-optical trap (MOT) is formed around the suspended waveguide by emitting a plurality of cooling beams and a repump through the substrate opening. Evanescent fields are established above the suspended waveguide by coupling two trapping beams through the suspended waveguide, which trapping beams are red-detuned and blue-detuned with respect to the resonant optical transition of the atoms. By forming the MOT within the evanescent fields, an evanescent field optical trap (EFOT) is formed.

Suspended waveguides on membrane and needle structures towards photonic atom trap integrated platforms

A sealed, passively pumped, polycrystalline ceramic vacuum chamber and method for fabricating the chamber are disclosed. The body of the vacuum chamber is made from a polycrystalline ceramic, for example, alumina. The vacuum chamber includes one or more windows made from a transparent ceramic, for example, sapphire, to accommodate optical access, while remaining amorphous-glass free to minimize or eliminate helium permeation. The vacuum chamber components are joined via laser welding or furnace brazing and the completed chamber is bakeable at temperatures up to 400&#xb0; C. The vacuum chamber can operate at high or ultra-high vacuum pressures for an extended period through the use of one or more getter-based pumps. The vacuum chamber may include one or more atomic sources depending upon the application.

Passively pumped, polycrystalline ceramic high and ultra-high vacuum chambers

A compact laser source and a single sideband modulator used therein is disclosed. The compact laser source includes a seed laser and one or more channels, with each channel generating one or more output laser beams having corresponding different wavelengths. The compact laser source can be formed in whole or in part on a single optical motherboard to thereby minimize space and power requirements. By employing the disclosed single sideband modulator, harmonics in the generated output laser beams can be minimized. The compact laser source finds application in an atom interferometer (AI) system, which may be used to measure gravity, acceleration, or rotation of the AI system.

Growing community of inventors

Albuquerque, NM, United States of America

Jongmin Lee