A chip scale atomic clock (CSAC) includes a temperature stabilized physics system and a temperature stabilized electronics circuitry electrically coupled to the temperature stabilized physics system. Atomic clocks utilize an optical signal having a frequency component. The temperature stabilization increases frequency stability. The temperature stabilized physics system includes a vapor cell and a magnetic field coil, and is enclosed in a magnetic shield. When an ambient temperature of a chip scale atomic clock increases, fluid is extended away, due to thermal expansion, from at least one reservoir towards or away from a thermally isolated subsystem in at least one of the temperature stabilized electronics circuitry and the temperature stabilized physics system.

A chip scale atomic clock (CSAC) includes a temperature stabilized physics system and a temperature stabilized electronics circuitry electrically coupled to the temperature stabilized physics system. Atomic clocks utilize an optical signal having a frequency component. The temperature stabilization increases frequency stability. The temperature stabilized physics system includes a vapor cell and a magnetic field coil, and is enclosed in a magnetic shield. When an ambient temperature of a chip scale atomic clock increases, fluid is extended away, due to thermal expansion, from at least one reservoir towards or away from a thermally isolated subsystem in at least one of the temperature stabilized electronics circuitry and the temperature stabilized physics system.

In some embodiments, two light beams having different frequencies can be counter-propagated through an atomic absorber having an atomic transition frequency approximately equal to the sum of the frequencies of the two beams. When the beams are appropriately tuned, the atomic absorber absorbs significant amount of light of at least the lower power beam. The amount of light remaining after the absorber is an indication of how well the frequencies are tuned to the absorber. At least one of the beam frequencies has an FM modulation applied prior to the absorber. This means the phase of the remaining light compared to the FM modulation, along with the intensity of the remaining light, can be used to provide a first feedback signal to adjust the frequencies of the beams to match the absorber frequency. Finally, both beams have amplitude modulation applied before the absorber. Comparing the response of the first feedback signal to the AM modulation frequency generates an intensity ratio feedback signal used to adjust the power of at least one of the beams and realize the zero light shift condition.

In some embodiments, two light beams having different frequencies can be counter-propagated through an atomic absorber having an atomic transition frequency approximately equal to the sum of the frequencies of the two beams. When the beams are appropriately tuned, the atomic absorber absorbs significant amount of light of at least the lower power beam. The amount of light remaining after the absorber is an indication of how well the frequencies are tuned to the absorber. At least one of the beam frequencies has an FM modulation applied prior to the absorber. This means the phase of the remaining light compared to the FM modulation, along with the intensity of the remaining light, can be used to provide a first feedback signal to adjust the frequencies of the beams to match the absorber frequency. Finally, both beams have amplitude modulation applied before the absorber. Comparing the response of the first feedback signal to the AM modulation frequency generates an intensity ratio feedback signal used to adjust the power of at least one of the beams and realize the zero light shift condition.

A molecular clock which utilizes a rotational spectrum of gaseous molecules in a sub-THz region for clock stabilization is described. The molecular clock has a fast start-up characteristic and is also robust against mechanical vibration or variation of electromagnetic field. Also described is a chip-scale implementation of a molecular clock. In an embodiment, a molecular clock chipset only consumes a DC power of 66 mW. While providing a highly stable, compact and energy efficient time generator of portable devices.

A molecular clock which utilizes a rotational spectrum of gaseous molecules in a sub-THz region for clock stabilization is described. The molecular clock has a fast start-up characteristic and is also robust against mechanical vibration or variation of electromagnetic field. Also described is a chip-scale implementation of a molecular clock. In an embodiment, a molecular clock chipset only consumes a DC power of 66 mW. While providing a highly stable, compact and energy efficient time generator of portable devices.

A clock generator includes a hermetically sealed cavity and clock generation circuitry. A dipolar molecule that exhibits a quantum rotational state transition at a fixed frequency is disposed in the cavity. The clock generation circuitry is configured to generate an output clock signal based on the fixed frequency of the dipolar molecule. The clock generation circuitry includes a detector circuit, a multiplier, and reference oscillator control circuitry. The detector circuit is coupled to the cavity, and is configured to generate a detection signal representative of an amplitude of a signal at an output of the cavity. The multiplier is coupled to the detector circuit, and is configured to multiply the detection signal with a mixing signal to produce a derivative of the detection signal. The reference oscillator control circuitry is configured to set a frequency of a reference oscillator based on the derivative of the detection signal.

A clock generator includes a hermetically sealed cavity and clock generation circuitry. A dipolar molecule that exhibits a quantum rotational state transition at a fixed frequency is disposed in the cavity. The clock generation circuitry is configured to generate an output clock signal based on the fixed frequency of the dipolar molecule. The clock generation circuitry includes a detector circuit, a multiplier, and reference oscillator control circuitry. The detector circuit is coupled to the cavity, and is configured to generate a detection signal representative of an amplitude of a signal at an output of the cavity. The multiplier is coupled to the detector circuit, and is configured to multiply the detection signal with a mixing signal to produce a derivative of the detection signal. The reference oscillator control circuitry is configured to set a frequency of a reference oscillator based on the derivative of the detection signal.

An atomic oscillator includes an atom cell that accommodates an alkali metal atom therein, a container that houses the atom cell, a substrate on which the container is disposed, and a thermally insulating mount that is fixed to the substrate and positions the container relative to the substrate.

An atomic oscillator includes an atom cell that accommodates an alkali metal atom therein, a container that houses the atom cell, a substrate on which the container is disposed, and a thermally insulating mount that is fixed to the substrate and positions the container relative to the substrate.