Continuous tunable RF sensor using rydberg atoms with high transmissivity

Patent metadata

Field	Value
Publication number	US-11940374-B2
Application number	US-202117408215-A
Country	US
Kind code	B2
Filing date	Aug 20, 2021
Priority date	Jan 21, 2021
Publication date	Mar 26, 2024
Grant date	Mar 26, 2024

Abstract

A continuously tunable radio frequency (RF) sensor system is provided. The system includes a pump laser system that includes first and second pump lasers, at least one frequency modulator to modulate frequencies of first and second laser light from the pump lasers to first and second select frequencies, a switch system to selectively pass one of the first and second laser light, an amplifier to amplify the passed laser light, a frequency doubler to double the frequency of the amplified laser light to generate pump light. A laser source lock system is in communication with the pump laser system to ensure a frequency of the pump light is referenced to atoms in a vapor cell and provide a probe light. The pump light and probe light are transmitted through the vapor cell. A detector measures the probe light that passed through the vapor cell.

First claim

The invention claimed is:

1. A continuously tunable radio frequency (RF) sensor system, the sensor system comprising:
a vapor cell including alkali atoms;
an optical train including,
a laser source lock system configured to generate probe light of a first wavelength;
a pump laser system configured to generate pump light of a select second wavelength, the pump laser system including,
at least a first pump laser to generate a first laser light of the select second wavelength,
at least a second pump laser to generate a second laser light of the select second wavelength, the probe light in communication with the first pump laser and the second pump laser to ensure a frequency of the first pump laser and the second pump laser is referenced to the alkali atoms in the vapor cell,
at least one frequency modulator configured to provide a local oscillator and at least one of frequency offsets, time-varying offsets and frequency sweeps to the first laser light and the second laser light,

a switch system configured to pass one of the first laser light and the second laser light to an amplifier, and
a frequency doubler coupled to receive amplified laser light from the amplifier, the frequency doubler configured to double a frequency of the amplified laser light to generate the pump light, the pump light and probe light transmitted through the vapor cell; and

a detector configured to measure the probe light passed through the vapor cell to determine if an RF signal has been detected.

2. The sensor system of claim 1 , wherein the switch system includes resonator based switches.

3. The sensor system of claim 1 , wherein the at least one frequency modulator further comprising:
a first frequency modulator to modulate the first laser light; and
a second frequency modulator to modulate the second laser light.

4. The sensor system of claim 1 , wherein the at least one frequency modulator further comprises:
an array of lithium niobate electro-optic modulators; and
serrodyne frequency shifters.

5. The sensor system of claim 1 , wherein the local oscillator provided by the at least one frequency modulator allows a heterodyne measurement at the detector.

6. The sensor system of claim 1 , further comprising:
a first optical phase lock loop in communication with a master laser of the laser source lock system;
a frequency comb in communication with the first optical phase lock loop; and
second optical phase lock loop in communication with the frequency comb, the second optical phase loop further in communication with the first and second pump lasers.

7. The sensor system of claim 6 , wherein an absolute reference of the probe light is locked to a saturated absorption spectroscopy.

8. The sensor system of claim 6 , further comprising:
an optical filter to filter the probe light from the master laser.

9. The sensor system of claim 1 , further comprising:
at least one controller in communication with the at least one frequency modulator, switch system and detector;
a memory to store at least one of operational instructions for the controller and information related to detected RF signals, the controller in communication with the memory; and
an input/output in communication with the controller configured to at least one of convey detected RF signals and provided an interface that allows a user to provide operating instructions that are stored in the memory.

10. A continuously tunable radio frequency (RF) sensor system, the sensor system comprising:
a vapor cell including alkali atoms;
an optical train including,
a laser source lock system including,
a master laser to generate a probe light of a first wavelength,
a first optical phase lock loop in communication with a master laser of the laser source lock system,
a frequency comb in communication with the first optical phase lock loop, and
a second optical phase lock loop in communication with the frequency comb;

a pump laser system configured to generate pump light of a select second wavelength, the pump laser system including,
at least a first pump laser to generate a first laser light of the select second wavelength,
at least a second pump laser to generate a second laser light of the select second wavelength, the first pump laser and the second pump laser in communication with the second optical phase loop to provide frequency references for the first pump laser and the second pump laser,
at least one frequency modulator configured to provide a local oscillator and at least one of frequency offsets, time-varying offsets and frequency sweeps to the first laser light and the second laser light,
a resonator based fast switch system configured to pass one of the first laser light and the second laser light to an amplifier, and
a frequency doubler coupled to receive amplified laser light from the amplifier, the frequency doubler configured to double a frequency of the amplified laser light to generate the pump light, the pump light and probe light transmitted through the vapor cell; and

a detector configured to measure the probe light passed through the vapor cell to determine if an RF signal has been detected.

11. The sensor system of claim 10 , wherein the at least one frequency modulator further comprises:
a first frequency modulator to modulate the first laser light; and
a second frequency modulator to modulate the second laser light.

12. The sensor system of claim 10 , wherein the at least one frequency modulator includes an array of lithium niobate electro-optic modulators.

13. A method of detecting radio frequency (RF) signals, the method comprising:
generating a first laser light of a first wavelength with a first laser;
generating a second laser light of the first wavelength with a second laser;
providing frequency references for the first laser light and the second laser light with a probe light having a second wavelength;
selectively switching between passing the first laser light and the second laser light to an amplifier;
modulating the first laser light and second laser light to select frequencies before the first laser light and the second laser light are selectively passed to the amplifier;
amplifying the passed first laser light and second laser light with the amplifier;
doubling the frequency of the amplified first laser light and second laser light to generate pump light;
passing the pump light and the probe light through a vapor cell; and
measuring the probe light to determine if an RF signals is present.

14. The method of claim 13 , wherein the switching between the passing of the first laser light and the second laser light to an amplifier is provided with resonator based switches.

15. The method of claim 13 , further comprising:
pre-tuning the frequency of first laser light and second laser lights before switching to pass the first laser light and the second laser light.

16. The method of claim 13 , further comprising:
generating the probe light with a laser source system.

17. The method of claim 16 , wherein the generating the probe light further comprises:
locking an absolute reference of a master laser to a saturation absorption spectroscopy; and
passing an output of the master laser through an optical filter that is locked to a transmission peak with a proportional-integral-derivative controller to generate master laser light with a narrow line-width.

18. The method of claim 13 , wherein providing frequency references for the first laser light and the second laser light with a probe light having a second wavelength further compr

Assignees

• Honeywell Int Inc

Inventors

• Nelson Karl D
• Puckett Matthew Wade
• Solmeyer Neal Eldrich
• Compton Robert

Classifications

• G01N21/17 Primary

  Systems in which incident light is modified in accordance with the properties of the material investigated (where the material investigated is optically excited causing a change in wavelength of the incident light G01N21/63) · CPC title

• G02F1/3507

  Arrangements comprising two or more nonlinear optical devices · CPC title

• G02F1/3551

  Crystals · CPC title

• G02F1/37 Primary

  for second-harmonic generation {(G02F1/3532 takes precedence)} · CPC title

• H01S3/0092

  Nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity (nonlinear frequency conversion per se G02F1/35) · CPC title