Systems and methods for correction of frequency spectrum in dual comb spectroscopy

• US 10,060,796 B2
• Filed: 04/25/2016
• Issued: 08/28/2018
• Est. Priority Date: 04/25/2016
• Status: Active Grant

• Current Assignee: Morpho Detection (Safran SA)
• Original Assignee: Morpho Detection (Safran SA)
• Inventors: Bekal, Anish, Vartak, Sameer Dinkar, Sharma, Rachit
• Primary Examiner(s): Geisel, Kara E
• Assistant Examiner(s): Prieto, Violeta A
• Application Number:
  US15/137,564
• Publication Number:
  US 20170307443A1
• Time in Patent Office: 855 Days
• CPC Class Codes: G01J 2003/2866 Markers; Calibrating of scan
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/28 Investigating the spectrum using colour filters G01J3/51
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 3/42 Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry beam switching arrangements G01J3/08
• CPC Class Codes: G01J 3/4338 Frequency modulated spectrometry
• CPC Class Codes: G01J 3/457 Correlation spectrometry, e.g. of the intensity G01J3/453 takes precedence

Abstract

A method for correcting frequency offset in a dual comb spectroscopy system is provided. The method includes causing a first laser (L1) generator to transmit L1 pulses at a repetition rate of a first frequency and causing a second laser (L2) generator to transmit L2 pulses at a repetition rate of a second frequency. The method also includes interrogating a reference material using a combination of the L1 pulses and the L2 pulses and capturing reference cell pulses. The method further includes interrogating a material of interest using the L1 pulses and capturing material of interest pulses. The method includes determining a frequency jitter based on the captured reference cell pulses and the combination of the captured material of interest pulses and the L2 pulses.

Claims

1. A method for correcting frequency offset in a dual comb spectroscopy system, said method comprising:

causing a first laser (L1) generator to transmit L1 pulses at a repetition rate of a first frequency;

causing a second laser (L2) generator to transmit L2 pulses at a repetition rate of a second frequency, the second frequency different from the first frequency;

interrogating a reference material using a combination of a first portion of the L1 pulses and a first portion of the L2 pulses;

capturing reference cell pulses that include the combination of the first portion of the L1 pulses and the first portion of the L2 pulses that interrogated the reference material;

interrogating a material of interest using a second portion of the L1 pulses;

capturing material of interest pulses that include the second portion of the L1 pulses that interrogated the material of interest; and

determining a frequency jitter based on the captured reference cell pulses and the combination of the captured material of interest pulses and a second portion of the L2 pulses.

2. The method of claim 1, wherein interrogating the material of interest includes interrogating the material of interest using the second portion of the power of the L1 pulses, wherein the second portion is 70-100%.

3. The method of claim 1, wherein interrogating the reference material includes interrogating the reference material using a combination of the first portion of the power of the L1 pulses and the first portion of the power of the L2 pulses, wherein the first portion of the power of the L1 pulses is 0-30% and the first portion of the power of the L2 pulses is 0-30%.

4. The method of claim 1, wherein interrogating the reference material includes interrogating the reference material at a predetermined concentration and a predetermined pressure.

5. The method of claim 1, wherein determining the frequency jitter includes determining the frequency jitter by transforming a plurality sections of the captured reference cell pulses and by cross-correlating each section with a first of the plurality of section of the capture reference cell pulses.

6. The method of claim 5, further comprising applying the determined frequency jitter to the combination of the captured material of interest pulses and a second portion of the L2 pulses.

7. The method of claim 6, further comprising determining whether the determined frequency jitter exceeds a predetermined jitter threshold.

8. The method of claim 7, further comprising causing a change in a pump power of said first laser generator in response to the determined frequency jitter exceeded the predetermined jitter threshold.

9. The method of claim 7, further comprising causing a change in a pump power of said second laser generator in response to the determined frequency jitter exceeded the predetermined jitter threshold.

10. The method of claim 8, wherein determining whether the determined frequency jitter exceeds a predetermined jitter threshold includes determining whether the determined frequency jitter exceeds the predetermined jitter threshold within a specific time period.

11. A frequency offset correction system for correcting frequency offset in a dual comb spectroscopy system, said frequency offset correction system comprising:

a first laser (L1) generator configured to transmit L1 pulses at a repetition rate of a first frequency;

a second laser (L2) generator configured to transmit L2 pulses at a repetition rate of a second frequency, the second frequency different from the first frequency;

a first combiner configured to combine a first portion of the L1 pulses and a first portion of the L2 pulses to interrogate a reference material;

a reference detector configured to capture reference material pulses that include a combination of the first portion of the L1 pulses and the first portion of the L2 pulses that interrogated the reference material;

an interrogation detector configured to capture material of interest pulses that include a second portion of the L1 pulses that interrogated the material of interest; and

a controller configured to cause the first laser generator and the second laser generator to correct for frequency offset the L1 pulses and the L2 pulses, respectively, based on the captured reference material pulses and the captured material of interest pulses.

12. The frequency offset correction system of claim 11, wherein said interrogation detector interrogates the material of interest using the second portion of the power of the L1 pulses, wherein the second portion is 70-100%.

13. The frequency offset correction system of claim 11, wherein said interrogation detector interrogates the reference material using a combination of the first portion of the power of the L1 pulses and the first portion of the power of the L2 pulses, wherein the first portion of the power of the L1 pulses is 0-30% and the first portion of the power of the L2 pulses is 0-30%.

14. The frequency offset correction system of claim 11, wherein said interrogation detector interrogates the reference material at a predetermined concentration and a predetermined pressure.

15. The frequency offset correction system of claim 11, wherein said controller determines the frequency jitter by transforming a plurality sections of the captured reference cell pulses and by cross-correlating each section with a first of the plurality of section of the capture reference cell pulses.

16. The frequency offset correction system of claim 15, wherein said controller is further configured to apply the determined frequency jitter to the combination of the captured material of interest pulses and a second portion of the L2 pulses.

17. The frequency offset correction system of claim 16, wherein said controller is further configured to determine whether the determined frequency jitter exceeds a predetermined jitter threshold.

18. The frequency offset correction system of claim 17, wherein said controller is further configured to cause a change in a pump power of said first laser generator in response to the determined frequency jitter exceeded the predetermined jitter threshold.

19. The frequency offset correction system of claim 17, wherein said controller is further configured to cause a change in a pump power of said second laser generator in response to the determined frequency jitter exceeded the predetermined jitter threshold.

20. A controller for correcting frequency offset in a dual comb spectroscopy system, said controller including a processor coupled to a memory device, said controller is configured to correct frequency offset by:

causing a first laser (L1) generator to transmit L1 pulses at a repetition rate of a first frequency;

causing a second laser (L2) generator to transmit L2 pulses at a repetition rate of a second frequency, the second frequency different from the first frequency;

capturing reference cell pulses that include the combination of the first portion of the L1 pulses and the first portion of the L2 pulses that interrogated a reference material;

capturing material of interest pulses that include the second portion of the L1 pulses that interrogated a material of interest;

determining a frequency jitter based on the captured reference cell pulses and the combination of the captured material of interest pulses and a second portion of the L2 pulses;

determining whether the determined frequency jitter exceeds a predetermined jitter threshold, and

in response to the determined frequency jitter exceeded the predetermined jitter threshold, causing a change in at least one of the following a pump power of the first laser generator and a pump power of the second laser generator.