Provided is an atomic vapor cell, for atomic or molecular spectroscopy, optical pumping, and/or spin-based atomic sensing, that includes a host substrate and defined there within a buried or non-buried chamber laser written in the host substrate without the need of a mask or photoresist, with either planar or three-dimensional geometry, and intended to contain an atomic vapor.

Also provided are an integrated atomic/photonic device and an apparatus, in both cases including the presently disclosed atomic vapor cell, and a method for fabricating the presently disclosed atomic vapor cell.

An atomic clock employs hybrid long/short quantum clock frequency regulation wherein each of a series of regulation cycles includes a relatively long (four Ramsey-cycle) combination error signal (CES) cycle and plural relatively short (two Ramsey-cycle) single error signal (SES) cycles. The CES cycles provide for better long-term stability than can be provided using only SES cycles. However, including the SES cycles between CES cycles improves short term stability with negligible diminishment of long-term stability.

An atomic cell filled with an alkali metal includes: a substrate; a first coating layer provided on an inner wall of the substrate and derived from a first molecule; a second coating layer provided on the first coating layer, and derived from a second molecule having a non-polar group and a reactive group that undergoes a desorption reaction with the first molecule; and a third coating layer provided on the second coating layer and derived from a non-polar third molecule. The third coating layer has a degree of crystallinity of 70% or more.

A frequency-modulated spectrometry (FMS) output is used to stabilize an atomic clock by serving as an error signal to regulate the clock's oscillator frequency. Rubidium 87 atoms are localized within a hermetically sealed cell using an optical (e.g., magneto-optical) trap. The oscillator output is modulated by a sinusoidal radio frequency signal and the modulated signal is then frequency doubled to provide a modulated 788 nm probe signal. The probe signal excites the atoms, so they emit 775.8 nm fluorescence. A spectral filter is used to block 788 nm scatter from reaching a photodetector, but also blocks 775.8 nm fluorescence with an angle of incidence larger than 8° relative to a perpendicular to the spectral filter. The localized atoms lie within a conical volume defined by the 8° effective angle of incidence so an FMS output with a high signal-to-noise ratio is obtained.

An atomic clock employs alkali metal atoms such as cesium normally used for microwave atomic clocks but with optical stimulation. While alkali metals provide light emissions having a spectral width being as much as 10.sup.7 wider (and hence less precise) than alkali earth materials commonly targeted for optical atomic clocks, the present inventors have determined that this disadvantage is significantly reduced by improved signal-to-noise ratio in the obtained signal making practical an atomic clock with improved size, weight, and power consumption.

In some embodiments, a molecular clock includes a waveguide gas cell containing gas molecules having a rotational spectral line with a first frequency a voltage-controlled oscillator (VCO) to generate a clock signal, a transmitter referenced to the clock signal to generate a probing signal for transmission through the waveguide gas cell, and a receiver to receive the probing signal transmitted through the waveguide gas cell and interacting with gas molecules. The receiver can include a filter circuit configured to filter out even harmonic components from the received signal and can further include a lock-in detector to generate an error signal indicating an offset between the first frequency and the second frequency. The error signal is fed back to control generation of the VCO clock signal.

According to some aspects of the present disclosure, an atomic clock and methods of forming and/or using an atomic clock are disclosed. In one embodiment, an atomic clock includes: a light source configured to illuminate a resonance vapor cell; a narrowband optical filter disposed between the light source and the resonance vapor cell and arranged such that light emitted from the light source passes through the narrowband optical filter and illuminates the resonance vapor cell. The resonance vapor cell is configured to emit a signal corresponding to a hyperfine transition frequency in response to illumination from the light source, and a filter cell is disposed between the light source and the resonance vapor cell and configured to generate optical pumping. An optical detector is configured to detect the emitted signal corresponding to the hyperfine transition frequency.

In a described example, an apparatus includes: a package substrate having a device side surface and a board side surface opposite the device side surface; a physics cell mounted on the device side surface having a first end and a second end; a first opening extending through the package substrate and lined with a conductor, aligned with the first end; a second opening extending through the package substrate and lined with the conductor, aligned with the second end; a millimeter wave transmitter module on the board side, having a millimeter wave transfer structure including a transmission line coupled to an antenna aligned with the first opening; and a millimeter wave receiver module mounted on the board side surface of the package substrate and having a millimeter wave transfer structure including a transmission line coupled to an antenna for receiving millimeter wave signals, aligned with the second opening.

A physics cell includes a sealed glass vial that contains a high-purity dipolar gas (e.g., OCS) at a low pressure (e.g., between about 0.01 millibar and 0.2 millibar). The vial can be sealed using a laser cutting process that involves only local heating of the vial that does not denature the bulk of the contained gas. One or more electromagnetically translucent windows or vial-end access points provide access to electromagnetic waves launched or received by one or more electromagnetic antennas at a frequency that is adjusted to match the quantum transition frequency of the gas based on a detected maximum absorption frequency. The glass-vial physics cell can be fabricated at lower cost than physics cells fabricated from bonded wafers. Multiple vials can be joined by a waveguide in an enclosure so that launch and receive antennas can be provided at a single end of the vials.

This atomic resonator for causing a resonance frequency by CPT resonance includes: a gas cell having alkali metal atoms enclosed; a photodetector configured to detect light having passed through the gas cell and convert the light to an electric signal; a high-frequency oscillator configured to receive the electric signal and output the signal after a frequency thereof is divided by two; and a laser light source configured to modulate and introduce, into the gas cell, light based on the signal output from the high-frequency oscillator. The high-frequency oscillator has an injection-locked frequency divider circuit including an acoustic resonator as an oscillation element.