SYSTEM AND METHOD FOR GENERATING AN OPTICAL FREQUENCY STANDARD
First Claim
1. A system for generating an optical frequency standard comprising:
- a first laser source configured to generate a first laser output at a first frequency;
a first second harmonic generator configured to receive as an input the first laser output to generate a frequency-doubled first laser output at a doubled first frequency;
a second laser source configured to generate a second laser output at a second frequency different from the first frequency;
a second second harmonic generator configured to receive as an input the second laser output to form a frequency-doubled second laser output at a doubled second frequency;
a two-colour stabilisation arrangement configured to stabilise a sum of the doubled first and the doubled second frequencies including;
an interaction region incorporating a laser active material, the laser active material having a two-photon transition from a first energy level to a second energy level, the interaction region configured to receive as an input the frequency-doubled first laser output and the frequency-doubled second laser output, the frequency-doubled first laser output and the frequency-doubled second laser output selected to together cause the two-photon transition from the first energy level to the second energy level using an intermediate energy level to enhance the two-photon transition rate; and
a detector configured to detect an indicator of the two-photon transition occurring in the interaction region, the detector generating a frequency stabilisation signal for modifying either the first laser output or the second laser output to stabilise the sum of the doubled first frequency and the doubled second frequency originating from the first and second laser sources to the two-photon transition based on the indicator;
a stabilised optical output generator including a sum frequency generator configured to receive as an input the first laser output and the second laser output to generate a stabilised optical output with a frequency corresponding to the optical frequency standard.
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Accused Products
Abstract
A system for generating an optical frequency standard is described. The system comprises a first laser source for generating a first laser output at a first frequency, a first second harmonic generator receiving as an input the first laser output to generate a frequency-doubled first laser output at a doubled first frequency, a second laser source for generating a second laser output at a second frequency different from the first frequency and a second harmonic generator receiving as an input the second laser output to form a frequency-doubled second laser output at a doubled second frequency. The system further includes a two-colour stabilisation arrangement to stabilise a sum of the doubled first and the doubled second frequencies that includes an interaction region incorporating a laser active material having a two-photon transition from a first energy level to a second energy level which receives as an input the frequency-doubled first laser output and the frequency-doubled second laser output where these outputs are selected to together cause the two-photon transition from the first energy level to the second energy level using an intermediate energy level to enhance the two-photon transition rate. The system also includes a detector to detect an indicator of the two-photon transition occurring in the interaction region which generates a frequency stabilisation signal for modifying either the first laser output or the second laser output to stabilise the sum of the doubled first frequency and the doubled second frequency to the two-photon transition based on the indicator and a stabilised optical output generator that includes a sum frequency generator receiving as an input the first laser output and the second laser output to generate a stabilised optical output with a frequency corresponding to the optical frequency standard.
0 Citations
24 Claims
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1. A system for generating an optical frequency standard comprising:
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a first laser source configured to generate a first laser output at a first frequency; a first second harmonic generator configured to receive as an input the first laser output to generate a frequency-doubled first laser output at a doubled first frequency; a second laser source configured to generate a second laser output at a second frequency different from the first frequency; a second second harmonic generator configured to receive as an input the second laser output to form a frequency-doubled second laser output at a doubled second frequency; a two-colour stabilisation arrangement configured to stabilise a sum of the doubled first and the doubled second frequencies including; an interaction region incorporating a laser active material, the laser active material having a two-photon transition from a first energy level to a second energy level, the interaction region configured to receive as an input the frequency-doubled first laser output and the frequency-doubled second laser output, the frequency-doubled first laser output and the frequency-doubled second laser output selected to together cause the two-photon transition from the first energy level to the second energy level using an intermediate energy level to enhance the two-photon transition rate; and a detector configured to detect an indicator of the two-photon transition occurring in the interaction region, the detector generating a frequency stabilisation signal for modifying either the first laser output or the second laser output to stabilise the sum of the doubled first frequency and the doubled second frequency originating from the first and second laser sources to the two-photon transition based on the indicator; a stabilised optical output generator including a sum frequency generator configured to receive as an input the first laser output and the second laser output to generate a stabilised optical output with a frequency corresponding to the optical frequency standard. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for generating an optical frequency standard comprising:
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generating a first laser output at a first frequency; generating a frequency-doubled first laser output from the first laser output at a doubled first frequency; generating a second laser output at a second frequency different from the first frequency; generating a frequency-doubled second laser output from the second laser output at a doubled second frequency; stabilising a sum of the doubled first and the doubled second frequencies by generating a two-photon transition from a first energy level to a second energy level in an interaction region, the interaction region configured to receive as an input the frequency-doubled first laser output and the frequency-doubled second laser output, the frequency-doubled first laser output and the frequency-doubled second laser output selected to together cause the two-photon transition from the first energy level to the second energy level using an intermediate energy level to enhance the two-photon transition rate; and detecting an indicator of the two-photon transition occurring in the interaction region to generate a frequency stabilisation signal; modifying either the first laser output or the second laser output in accordance with the frequency stabilisation signal to stabilise the sum of the doubled first frequency and the doubled second frequency originating from the first and second laser sources to the two-photon transition based on the indicator; and generating a stabilised optical output with a frequency corresponding to the optical frequency standard by frequency summing the first laser output and the second laser output. - View Dependent Claims (18)
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19. A system for generating an optical frequency standard stabilised to twice the wavelength of an input optical frequency standard including:
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a first optical input configured to receive the input optical frequency standard; a second optical input configured to receive the laser output of a laser source whose frequency is to be stabilised; a frequency stabilisation arrangement including; a second harmonic generator configured to frequency double the laser output to generate a frequency doubled laser output; and a frequency comparison module configured to compare the frequency of the frequency doubled laser output to the input optical frequency standard to generate a frequency control signal to frequency stabilise the laser output of the laser source to twice the wavelength of the optical frequency standard. - View Dependent Claims (20, 21, 22, 23)
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24. An optical frequency standard system comprising:
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first and second lasers and respective frequency doublers to generate frequency doubled outputs of the first and second lasers; a gas cell based two-colour stabilisation arrangement to frequency stabilise the sum of the frequency doubled outputs of the first and second lasers; a frequency summer to sum the frequencies of the first and second lasers to generate the optical frequency standard.
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Specification