SU1452421A1 - Method of stabilization of laser radiation frequency - Google Patents

Abstract

The invention relates to the field of quantum electronics and can be used in the development of frequency-stabilized lasers. The purpose of the invention is to increase the frequency stability of the laser. The difference frequency signal is modulated by applying a transverse alternating magnetic field to the active medium or by passing a pulsating discharge current. The resulting frequency modulated error signal is used to adjust the length of the resonator. The resonator length adjustment is performed by minimizing the deviation of the difference frequency signal corresponding to the center of the gain circuit, which is determined by the properties of the active medium and does not depend on the frequency of the reference oscillator. This increases the frequency stability of the laser. 3 il.

Description

The invention relates to the field of quantum electronics and can be used in the development of frequency-stabilized lasers.

The aim of the invention is to improve the stability of the frequency of the laser radiation.

Fig. I shows a diagram of the device for stabilizing the frequency of laser radiation in accordance with the proposed method; Fig. 2 is a graph showing the variation in the magnetic field intensity applied to the active medium of a laser as a function of time; FIG. 3 is a plot of the difference frequency detuning of the resonator for three values of the magnetic field.

A device for implementing a method for stabilizing a laser radiation frequency contains an activating element I with a phase isotropic resonator placed in a magnet 2 creating a transverse magnetic field and an electromagnet 3 creating an alternating magnetic field. The photo-reception principle is connected with the ontuqecKH element 4. The receiver is connected to a 4acTOTtBiiM detector 5 containing a phase detector 6, a low-frequency filter 7 and a generator 8 controlled by current. The frequency of the detector 5 is connected to the blue detector of the 9 corrections of cnm zakrm 10 and the power amplifier 11 Pre-installation device 12 is intended for installation, I.JI V

The values of the length of the cavity. A low frequency generator 13 is connected to an electromagnet 3 (to create an alternating magnetic field and to the reference input of a synchronous detector.

The method of frequency stabilization is as follows.

On the active medium, placed in a phase-anisotrol resonator, impose a transverse magnetic field created by a magnet 2, the value of which is equal to or more - the minimum magnetic field strength, providing a two-frequency mode with orthogonal polarization of laser radiation

In addition, an alternating magnetic field is created by the electromagnet 3, the amplitude of which is H «iH -H, (see FIG. 2).

The dependence of the difference frequency on the detuning of the resonator, taken out of experimentation (in winter, is shown in Fig. 3 with | ae magnetic magnetic fields (H) or | grounding currents (I); As the ijarHHTHoro field or discharge current increases, the difference frequency. If the 5-frequency frequency f is greater than the center difference frequency 1, i.e., -fp fp (,. s TO In area 4 as the distance from the point fp is corresponding to zero-detuning, the value of the difference frequency in area 15 increases as the distance from the point corresponding to zero, Power dissipation of the resonator To a frequency equal to f, the value of the residual frequency decreases (see Fig. 3). This is the deviation of the part that has an Inumn in the center of the circuit. From the output of the active element with a phase anisotropic resonator, the laser radiation containing the difference frequency fp, modulated in frequency using a low-frequency generator 13 connected to an electromagnet 3, creating a pulsating transverse magnetic field, is directed to a photo-receiving 4, where it is converted into an electrical signal. The amplifier in the amplifier signal is directed to the frequencies of the 1st detector 5, which is a coherent detector with phase locked loop frequency (PLL) After capturing the frequency in the frequency generator pjiTop detector, controlled by "S current 8 frequency)

52421 S

The detector 5 is set at the frequency fp, and at the output of the low-frequency fil- ter 7, a variable low-frequency signal modulating the difference frequency is selected, the amplitude and phase of which depend on the position of the preset cavity length relative to the zero resonator alignment. Further, this low-frequency signal is fed to the synchro detector 9, to another input of which a low-frequency generator 13 is connected, simultaneously modulating a transverse magnetic field.

At the output of the synchronous detector, after the corrective link 10, the misalignment cHrHBjT is released, propagating, and the ionic detuning of the resonator, 20 of which corresponds to the position of the detuning. After amplification in amplification, this error signal is fed to the resonator length-controlling element 14. 2B The control element is connected so that increasing the amplitude of the error signal causes an increase or decrease in the resonator length, respectively, or negative polarity of the error signal, ,

Thus, by obtaining a frequency-modulated difference frequency signal and adjusting the length 35 of the resonator to the difference frequency deviation corresponding to the center of the gain circuit, the frequency stability of the laser radiation is increased.

40 The method is independent of the stability of the reference oscillator, the signal from which varies over time. It is rather difficult to obtain a high frequency stability of the reference oscillator, since the contour of the amplification line is a natural reference and does not depend on external influences,

Example, The laser frequency is stabilized by a length of 50–23.5 cm with a phase-anisotropic resonator according to a difference frequency signal, & D dulled by the application of an alternating magnetic field with a voltage of 300 K) and a voltage of 60 K AC. The system-55 topic of automatic frequency control (AFC) contains the FD-263 photodetector, frequency and synchronous detectors collected on Harris chips, controlled by the YGD (w element is a helix, wound and then ac30

LNG element, power amplifier, s. powerful transistor CT-827. Optical frequency instability measurements of the optical frequency were carried out using an optical heterodyne method; a frequency-stable laser with frequency instability is used as a reference laser. The resulting frequency instability is obtained.

TaKiiM method allows to increase the frequency stability of the laser radiation by at least 2 times,

;

In addition, the method allows the laser wavelength to be measured and will enable the design of the AFC as a monolithic integrated circuit.

The formula and the method of bouting a method of stabilizing the frequency of a laser with a phase-anisotropic resonator, which imposes a transverse magnetic field on the active medium of the laser, separating the signal of the difference frequency between orthogonal polarized full fields after

10 by adjusting the optical length of the resonator, characterized in that, in order to increase the frequency stability of the laser, the differential frequency signal is modulated on the active medium of the laser by the alternating alternating magnetic field or by passing a pulsed current through the active medium, and the length adjustment the resonator is carried out until reaching a minimum of the deviation of the difference frequency signal.

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Claims (1)

Formula and method A method of stabilizing the frequency of a laser with a phase-anisotropic resonator, which consists in applying a transverse magnetic field to the active medium of a laser, extracting a difference frequency signal between orthogonal polarized waves, and then adjusting the optical length of the resonator, characterized in that, in order to increase the stability of the laser radiation frequency, the difference frequency signal is modulated by applying a transverse alternating magnetic field to the active medium of the laser or by passing Res active medium pulsing of discharge current, and adjusts the length of the resonator is carried out until a minimum deviation of the difference frequency signal. Figure 1 FIG. g