SU1266429A1 - Method and apparatus for stabilizing laser radiation frequency by saturated absorption resonance - Google Patents

Abstract

1. Stabilization mode of the laser radiation frequency by –presoHaney (laser pulse 1, but duplicating the radiation frequency, determining the amplitude of the odd harmonic signal signal of the laser power oscillations and tuning the laser frequency to the line center ( , that, in order to increase the frequency reproducibility, the amplitude of the signal of the second odd harmonic of the oscillation power of the laser radiation is additionally determined, while both are not lower than the third fold these values are in the ratio K.KHHH2 wKh ("t o gDe k, n - harmonic numbers; /; A, .A - a ISI of the signals of these harmonics, µW;, / KI - ratio: the width of the resonance of the saturated absorption at half its height to the first width of the modulation frequency band of the laser radiation, and 2. The device for stabilizing the frequency of the laser radiation on the saturated resonance is absorbed, containing a laser-resonator, one mirror of which is fixed on the piezocorrector, and the second is a piezo-modulator and, connected to the piezoelectric modulator, a power source, the input of which is connected to the input of a signal generator module mod, a supportive signal generator, photocircuit, an optical optical amplifier with a laser resonator, a selective amplifier, a synchronous detector, the first input of which is connected to the output of a selective laser, The second input is connected to the output of the reference signal generator, the direct current connection, the input of which is connected to the output of the synchronous signal. Another detector, and an output with a piezocorrector, characterized in that, in order to increase the frequency reproducibility, a nonlinear signal mixer, two frequency synthesizers, were introduced into the device; the F and F transformation functions with. respectively, with (f, F) nf + F, 1 Fj (f, F) - kf + F, the output signal frequency where, of the first synthesizer, Hz; -frequency of the signal at the output of the second synthesizer, Hz;

Description

f signal frequency at the first two shooters, Hz | F is the frequency of the signal at the second inputs of both synthesizers © spabi-gel with an attenuation coefficient. (.G GT-u fi., While the first frequency synthesizer tuners are connected to the 29th home of the phase shifter, the second codes to the output of the reference / signal generator output of the first synthesizer are connected to the first input of the second synthesizer, the second synthesizer code is connected to the second input the adder, the first input of the mixer is connected to the output of the photodetector, the second input is connected to the output of the adder, the output of the mixer is connected to the input of the selective amplifier.

The invention relates to quantum electronics, more precisely, frequency-acquired lasers and M07 can be used to create quantum-frequency standards.

The aim of the invention is to increase the reproducibility of the laser frequency. . .

In the extended stabilization method, the days of the laser radiation frequency are determined using the peso-to-saturation absorption method to simultaneously determine the values / amplitudes of the two two-odd-odd: HARMONIC signals of the oscillating radiation power of the laser.

K-h + th; (n)

K-h

(.fi 5.4-1 -f}

A + 11

where ks n numbers indicated tarmonik. And “, And the amplitudes of the signals e-1Sh harmonics 5

V is the ratio of the resonance width of the saturated absorption on the rug of its height Jt to the band width of the modulus of the cr-sh frequency of the laser radiation

It performs frequency tuning based on the central zero of the resulting Total signal.

In particular, in the proposed space for adjustment, the frequencies choose the third and fifth harmonics,

The drawing shows a block diagram of a device for stabilizing the frequency of a laser radiation about

The device is laser sourced, the resonator Is one mirror 2 of which is fixed on the pie-corrector e 3,

and the second mirror 4 is on a piezomodulator 5, with a laser element placed in a laser controller, an active element bn I, an absorbing cell 7, generator 8; a modulation signal connected to a modulator 5s; a generator 9 of a reference signal, a phase shifter 10 whose input connected to the output of the generator. 8, photodetector II, optically c - 0; associated with resonator I, selective 1st amplifier 1 2, synchronous detector fSj the first input of which is connected to the output of the selective amplifier 12, and the second input to the output code of the generator S ra 9, amplifier 1 D of constant current The code of which is connected to the output of the cr-sync detector 13, and the output of. With ° piezocorrector 3. The device is as follows: The same contains a non-linear mixer 15 whose input is connected to the input of the photodetector 11, and to the input of the amplifier 12, iz of the i6 synthesizer and. 17 frequencies with F and F transform functions, respectively, and in the particular case of choosing the third and fifth harmonics F, (f, F) ..W.E + F,

h

F) 5f -J-F,

F (f i

2

where f,

output frequency

first synthesizer 16j Hz | fj is the frequency of the signal at the output of the second synthesizer 17, Hz; f signal frequency at first

synthesizer inputs 165

17.-Tshch F - frequency signal on the second

I6 synthesizer inputs. 17 Hz

the first inputs of the synthesizers 16 and 17 are connected to the output of the phase shifter 10, and the second inputs are connected to the output of the generator 9, and the adder 18, the output of which is connected to the second input of the mixer 15, the first input is connected via the attenuator 19 to the output of the 16 frequency synthesizer, and the second the input is with the output of the synthesizer 17. The selective amplifier 12 is tuned to the frequency of the generator 9 of the reference signal.

The proposed method is implemented using the proposed device in a simple manner.

In the resonator, the generation of induced radiation, which interacts with the absorbed medium in cell 7, is excited. In the vicinity of the center of the absorption line, a saturated absorption resonance is formed. The signal of the generator 8 through the piezomodulator 5 modulates the frequency of the radiation sinusoidally. In this case, oscillations of the radiation power enriched with higher harmonics occur, the amplitude of the harmonics depends on the frequency of the radiation.

Generator 8 signal with frequency f, phase-shifted in phase shifter 10 to compensate for phase shift in amplifier 12, and generator signal 9 with frequency F are converted in synthesizers 16 and 17 into signals with frequencies 3f + F and 5f + F, respectively. The first of the received signals is attenuated by the attenuator 19, then the signals are added by the adder 18.

The oscillations of the radiation power are converted by the photodetector 11 into an electrical signal. The mixer 15 performs analog multiplication of this satellite with a signal arriving at the second input of the mixer 15 from the adder 18. From the complex signal acting at the output of the mixer 15, the selective amplifier 12 extracts and amplifies the signal at frequency F falling into its passband. A synchronous detector 13 produces a coherently varying voltage proportional to the amplitude of the signal sent to its first input from amplifier 12, and the cosine of the phase difference of this signal and the reference signal received from the second input 9. The voltage is amplified by the amplifier 14 direct current and its

output, acting on the piezocorrector 3, automatically adjusts the frequency to the zero value of the amplitude of the oscillations at the output of the amplifier 12.

The co-deficiency loosening attenuator 19 is set to

(I-fY,

where - the ratio of the width of the resonance

saturated absorption at half its height to the width of the modulation frequency band of the laser radiation.

The amplitudes of the signals from the outputs of the synthesizers 16, 17 are equal. At the output of the adder 18, a mixture of signal signals is formed at frequencies of 3f + F and 5f + F with a calibrated ratio of their amplitudes. This ratio can be established with high accuracy, for example, with an error not worse than Yu. The signals at the inputs of the mixer 15 can be represented as sums of the spectral components, then the signal at its output after analog multiplication of the input signals will look like

U (t) {V Ajcos (3-2rr-ft) -If AgCoa (52If ft) + U (t)

"Cos (3f + F; 2P (5f + F) 2Trt) - | - (Aj) C03 2TTFt -t-Ug (t),

where U (t) is the output signal, E;

V is the transfer coefficient of the mixer and photodetector,

 V / µW;

c (/ y + 1 - g

-T)

- attenuation coefficient

and, (t) ,.

and (t) is the signal components that do not fall within the passband of amplifier 12, V,

Thus, in mixer 15, the amplitudes of the third and fifth harmonics are added together, also accompanied by the transfer of their frequencies to the frequency F of the reference signal. In this case, the harmonic contributions to the total signal are calibrated and maintained with high accuracy. The result is a receipt. a bulk signal whose central zero coincides with the center d of the absorption line. I on the air, the proposed technical version of the iiiWeCKOe solution allows for the coincidence of the frequency of radiation with the center of asymmetry of the depucheniya of the stabilized laser. 1266429, 4 i of the formed resonance of the absorption wave and thereby increase the VDS; performance m frequency accuracy

Claims (2)

- 1. A method of stabilizing the laser radiation frequency by the saturated absorption resonance, which includes modulating the radiation frequency, determining the signal amplitude of the odd harmonic of the laser radiation power oscillations and adjusting the laser frequency to the center of the absorption line, characterized in that, in order to increase the frequency reproducibility further define the signal znachenie'amplitudy • second odd harmonic oscillation laser power at not less than Atom both third fold in the ratio of these values'·; e ") ^{2 / ^ + fx) K 'h} -A H + A g, where k, η - harmonic number; /' A _k. And _p are the amplitudes of the signals of these harmonics, μW; • 'is the ratio of the resonance width of the saturated absorption at half its height to (the modulation bandwidth of the' radiation frequency * of the daser) ^: and the radiation frequency is adjusted to the central zero of the resulting total signal. 2, A device for stabilizing the laser radiation frequency according to the saturated absorption reaeon * containing * a laser resonator, one mirror of which is mounted on the piezoelectric corrector, and the second is not a piezomodulator, a modulation signal generator connected to the piezoelectric modulator, phase shifter, the input of which is connected to the generator output modulation signal, a reference signal generator fotopryaemnkk, optically coupled with the laser resonator, a selective amplifier, a synchronous detector, a first input of which is connected to the output _f whether a selective usi- the second input is connected to the output of the reference signal generator, a DC amplifier, the input of which is connected to the output of the synchro nous detector, and the output is connected to a piezoelectric corrector, characterized in that, in order to increase the frequency reproducibility, a nonlinear mixer of signals is introduced into the device , two frequency synthesizers with 'functions F, and F ₂ transforms, respectively, with · f, “F, (f, F) = nf + F, f ₂ - F ₈ (f, F) - kf + F, where f - signal frequency at the output of the first synthesizer, Hz; f is the frequency of the signal at the output of the second synthesizer, Hz; , 1266429 f ”signal frequency at the first inputs of both synthesizers, Hz; F - signal frequency at the second inputs of both synthesizers, attenuator with attenuation coefficient. d * adder, with the first inputs of the frequency synthesizers connected to the output of the phase shifter, the second inputs ~ with the output of the reference / signal generator, the output of the first synthesizer connected to the first input of the adder, the output of the second synthesizer connected to the second input of the adder, the first input of the mixer connected with the output of the photodetector, the second input with the output of the adder, the output of the mixer is connected to the input of the selective amplifier.