RU2105387C1 - Method for conversion of optical light with arbitrary spectral width into power of electromagnetic waves in radio or lower bandwidth - Google Patents

Abstract

FIELD: power conversion, in particular, conversion of solar energy into electromagnetic waves of microwave bandwidth or to alternating or direct current, design of powerful filtering microwave amplifiers and microwave laser pumping oscillators. SUBSTANCE: method involves exposition of converting medium to light which is modulated in time by oscillations of constant frequency in radio or lower bandwidth so that frequency spectrum of modulated optical light for each carrier frequency of source non- modulated light corresponds to multiple frequencies which differ by constant modulation width value. Said converting medium is non- linear medium which has no inversion center and which runs conversion of modulated optical light by means of generation of electromagnetic oscillations or waves of radio or lower bandwidth. Said medium is transparent for both optical light and for frequencies of electromagnetic oscillations which are generated there. Converted power of electromagnetic waves of radio or lower bandwidth are accumulated using at least one electromagnetic resonator which resonance frequency is equal to frequency of generated electromagnetic oscillations and is equal to or is multiple of modulation frequency. Harmonics of modulated optical light and generated electromagnetic waves which power is accumulated using said at least one resonator interact in this medium in synchronism. EFFECT: increased functional capabilities. 32 cl, 5 dwg

Description

 The invention relates to the field of converting the energy of optical radiation with an arbitrary spectrum width into the energy of electromagnetic waves or waves of the radio range, for example, microwave (microwave) range, as well as into the energy of electromagnetic waves of the lower frequency range, in particular into the energy of electromagnetic (electrical) oscillations of industrial frequency (t .e. into alternating current energy) or arbitrarily low frequency (i.e. into direct current energy).

 The invention can find application for converting the energy of solar radiation into electromagnetic energy in the microwave range or into AC or DC energy (i.e., in solar energy), as well as in the development of powerful parametric microwave amplifiers and laser-pumped oscillators.

 A known method of converting the energy of optical radiation with an arbitrary width of the spectrum into energy of direct or alternating current, as well as into the energy of electromagnetic waves or waves of the radio range using photoemissive converters, which includes irradiating with optical radiation the medium, in this case, the medium (material) of the converter cathode, which transforms the energy of optical radiation in the form of heating this medium (material) of the cathode and the emission (emission) of electrons [1].

 To convert the energy of optical radiation in this way into the energy of electromagnetic waves or radio waves, the electric signal from the photoemission converter using the radio range generators, in particular the microwave range, is converted into vibration energy or radio waves.

 However, this method has a low efficiency (efficiency) of the considered energy conversion.

 A known photoelectric method for converting the energy of optical radiation with an arbitrary spectral width, adopted by us as a prototype, which includes irradiation with optical radiation of a medium in which the energy of optical radiation is converted [3]. This method allows the conversion of the energy of optical radiation with an arbitrary spectral width into electrical energy of direct or alternating current, and into the energy of electromagnetic waves or radio waves, in particular the microwave range. Moreover, the efficiency of this energy conversion in this method is higher than in the previous one.

 The conversion of light energy into direct or alternating current energy using the photoelectric method is based on the photovoltaic effect that occurs in inhomogeneous semiconductor media when they are irradiated with optical radiation. So, for example, if two semiconductors (n-semiconductor and p-semiconductor) are in contact, then when the contact surface is illuminated, an EMF appears between them and, as a result of this, an electric current occurs when the circuit is closed and electric energy is supplied to the consumer.

 This method allows you to convert both the energy of monochromatic optical radiation and the energy of optical radiation with a wide spectrum, such as solar radiation.

 To convert light energy into electromagnetic energy in the radio range by a photoelectric method, it is necessary to convert an electric signal from a photocell (or solar cell) using a radio range generator into oscillations or waves of the radio range.

 A similar energy conversion is planned to be used in the future in the operation of solar space power plants to transfer the converted energy to Earth. To this end, the electric current from solar cells located in a satellite solar power station, using microwave generators, is converted into useful microwave radiation, which is sent to the Earth using an onboard antenna.

 The disadvantage of this photoelectric method of converting the energy of optical radiation with an arbitrary spectrum width is the same as the previous method and consists in a low efficiency (coefficient of efficiency) of converting the energy of optical radiation with a wide spectrum, in particular solar radiation, into direct or alternating current energy, and in the electromagnetic energy of the radio range, which, as a rule, does not exceed 20%.

 The proposed invention solves the problem of increasing efficiency when converting the energy of optical radiation with an arbitrary width of the spectrum, including optical radiation with a wide spectrum, into electromagnetic energy of the radio or lower frequency range, in particular into microwave energy, or into alternating or direct current energy.

 This goal is achieved by the fact that in the known method of converting the energy of optical radiation with an arbitrary spectral width, which includes irradiating with optical radiation the medium in which the energy of optical radiation is converted, it is new that optical radiation is modulated in time by oscillations of a constant frequency of radio or lower frequency range so that in the frequency spectrum of the modulated optical radiation of each carrier frequency of the original unmodulated optical radiation (i.e., each frequency of optical radiation before modulation) corresponded to many frequencies equally spaced from each other by the modulation frequency, a nonlinear medium without an inversion center is used as a medium, in which the energy of the modulated optical radiation is converted in the form of electromagnetic waves generation or waves of the radio or lower frequency range, and which is transparent both for the frequencies of the optical range and for the frequencies of electromagnetic waves or waves generated in it, pre the generated energy of electromagnetic waves generated in a given medium or waves of the radio or lower frequency range is accumulated using one or more electromagnetic resonators, the resonant frequency of which coincides with the frequency of the generated electromagnetic waves or waves and is equal to or a multiple of the modulation frequency, while the synchronism condition for interacting in a given environment, harmonics (spectral components) of modulated optical radiation and generated oscillations or waves, energy I which is accumulated by one or more cavities.

 In this case, a higher efficiency of converting the energy of optical radiation into the energy of electromagnetic waves or waves of the radio or lower frequency range is achieved due to in-phase interactions in a transparent nonlinear medium without an inversion center between the many harmonics (spectral components) of the modulated optical radiation and the oscillations generated in this medium or waves of the radio or lower frequency range, followed by the accumulation of energy generated in the medium of oscillations or waves using e high-quality electromagnetic resonators in the above manner.

 The higher the quality factor of the resonators accumulating the converted energy, the more efficient is the process of energy conversion and the greater is the efficiency of this conversion.

 In the proposed method in a transparent nonlinear medium without an inversion center, when it is irradiated and the modulated optical radiation propagates in it, the energy of the modulated optical radiation is directly converted to electromagnetic energy of the radio or lower frequency range in the form of electromagnetic waves or waves with a frequency equal to or a multiple modulation frequency.

If L _{about a} nonlinear medium without an inversion center along the propagation direction of the modulated optical radiation is much shorter than the wavelength generated in this medium and accumulated with the help of resonators of electromagnetic radiation of the radio or lower frequency range, it can be assumed that electromagnetic waves of radio waves are generated in this medium or lower frequency range.

When the size of a nonlinear medium without an inversion center L _о is comparable to or greater than the wavelength generated in the given medium and accumulated with the help of resonators of electromagnetic radiation, we can assume that electromagnetic waves are generated in this medium.

 If the resonant frequency of the resonators is equal to the modulation frequency and the synchronism condition is fulfilled for harmonics of modulated optical radiation interacting in a nonlinear medium without a center of inversion and electromagnetic waves or waves generated in the medium with a frequency that coincides with the modulation frequency, then the optical radiation energy will be converted by the proposed method into electromagnetic energy oscillations or waves with a frequency equal to the modulation frequency and coinciding with the resonant frequency.

 If the resonant frequency of the resonators is a multiple of the modulation frequency and the synchronism condition is fulfilled for harmonics of modulated optical radiation and generated electromagnetic waves or waves with a frequency that is a multiple of the modulation frequency and coinciding with the resonant frequency of the resonators interacting in a nonlinear medium without an inversion center, then the energy of the optical radiation will be converted into energy electromagnetic waves or waves with a frequency multiple of the modulation frequency and coinciding with the resonant frequency.

The initial optical radiation, the energy of which is converted by the above method, can be both continuous operation and pulsed action. In the case of pulsed optical radiation, it is necessary that the pulse duration time T _i substantially exceeds the period of modulating oscillations T _modes (T _i > T _modes ).

 The width of the spectrum of the converted optical radiation in the present invention can be arbitrary. Thus, monochromatic or quasimonochromatic radiation, as well as radiation with a wide spectrum, can be used as the converted optical radiation.

 As nonlinear media without an inversion center, quadratic nonlinear media (media with quadratic nonlinearity) and cubic nonlinear media (media with cubic nonlinearity) placed in a constant electric (or magnetic) field can be used.

Quadratic nonlinear media include noncentrosymmetric crystals, for example, crystals of quartz (SiO ₂ ), KDP (KH ₂ PO ₄ ), urea (CO (NH ₂ ) ₂ )), etc.

 Cubic nonlinearity is characteristic of dielectric media with an inversion center: centrosymmetric crystals, gases, and liquids.

 However, a constant electric (or magnetic) field, polarizing an isotropic medium, deprives it of an inversion center.

 Therefore, a cubic nonlinear medium placed in a constant electric (or magnetic) field is also a nonlinear medium without a center of inversion.

 Nonlinear media without an inversion center used in the invention for efficient energy conversion by the proposed method should be transparent both for optical radiation frequencies and for vibration frequencies or waves of the radio or lower frequency range generated in this medium and accumulated in power with one or several resonators. Real nonlinear media without an inversion center, in particular a quartz crystal, have a finite optical transparency range and can also be transparent for frequencies in the radio or lower frequency range. The wider the optical transparency range of a given medium, the more efficiently this energy conversion proceeds and the higher the efficiency of this conversion.

 The geometry of the shape of nonlinear media without an inversion center in this invention may be different. In the case under consideration, along with voluminous extended nonlinear media, nonlinear media with fiber or waveguide geometry can be used, i.e. media with transverse dimensions commensurate with the wavelength of optical radiation.

 To implement modulation of the initial optical radiation in the present invention, the following types of modulation can be used: modulation of the initial optical radiation in phase or frequency by oscillations of a constant frequency of the radio or lower frequency range, including harmonic oscillations; amplitude modulation by periodic non-harmonic oscillations; pulse modulation.

 With these types of modulation, the basic condition for modulating the initial optical radiation in this invention is fulfilled, namely: in the frequency spectrum of the modulated optical radiation, each carrier frequency of the initial optical unmodulated radiation (i.e., each frequency of the initial radiation before modulation) corresponds to a plurality of frequencies, equally spaced from each other by the modulation frequency.

 To efficiently convert the energy of the initial optical radiation by the proposed method, it is necessary to fulfill the condition of synchronism for the harmonics (spectral components) interacting in a nonlinear medium of the modulated optical radiation and the vibrations or waves generated in this medium, the energy of which is accumulated using one or more resonators (the frequency of these generated and accumulated oscillations or waves coincides with the resonant frequency of the resonators and can be equal to or a multiple of the frequency odulyatsii).

In this case, the condition of synchronism is the condition for effective energy exchange during interaction in a nonlinear medium without a center of inversion of harmonics (spectral components) of the modulated initial radiation and oscillations or waves of the radio or lower frequency range generated in this medium, which consists in preserving certain phase relations between harmonics and generated vibrations or waves throughout the interaction area. In particular, the synchronism condition is fulfilled when the phase incursion over the entire interaction region of harmonics of modulated optical radiation and generated oscillations or waves relative to each other does not exceed π (180 ^o ).

In the present invention, there always exists a certain size of a nonlinear medium without an inversion center along the propagation direction of the modulated optical radiation: L _о ≤ L _coh (where L _coh is the length of the coherent interaction or the length of coherence), on which the synchronism condition is fulfilled automatically without special measures.

At this distance L _о ≤ L _coh, the phase incursion of all interacting harmonics of the modulated optical radiation and the oscillations or waves generated in a given medium relative to each other does not exceed π (180 ^o ).

To fulfill the condition of synchronism with the dimensions of a nonlinear medium without an inversion center along the propagation direction of the modulated optical radiation L _о > L _coh , special measures must be taken. For this purpose, for example, this nonlinear medium can be a set of contacting noncentrosymmetric crystals of size L _coh oriented with respect to each other so that nonlinear polarization waves each time pass through to another crystal experience a phase jump of π (180 ^o ).

 As electromagnetic resonators, with the help of which the energy generated in a nonlinear medium is stored without a center of inversion of oscillations or waves of the radio or lower frequency range, one can use either volume microwave resonators when converting to microwave electromagnetic energy, or oscillatory circuits when converting to electromagnetic energy lower frequency part of the radio range, as well as piezoelectric resonators, in particular, quartz resonators, dielectric resonators and n.

 A particular case of this invention is the conversion of the energy of optical radiation with an arbitrary spectral width into the energy of electromagnetic waves or microwave waves. In this case, using the emitting antenna, the converted microwave energy can be transmitted through free space. This transformation can be used in the development of wireless energy transmission systems through free space, for example, terrestrial power systems located in remote areas.

 Another important particular case of this invention is the conversion of the energy of optical radiation with an arbitrary spectral width into the energy of electromagnetic oscillations of low frequency, in particular, the energy of electromagnetic (electrical) oscillations of industrial frequency (i.e., AC energy) and electromagnetic energy ( electrical) vibrations of arbitrarily small frequency (i.e. into direct current energy).

 For a more efficient such conversion of energy, it is possible to convert the energy of optical radiation into the energy of electromagnetic waves or waves of the radio range, in particular the microwave range, in the above way, and then additionally use rectifier devices, for example microwave rectifiers, which make it possible to rectify the electromagnetic energy of oscillations or waves of the radio range, in particular Microwave range, in energy of direct or alternating current.

 Of all the types of modulation of the initial optical radiation, the simplest and most effective is the phase or frequency modulation by harmonic oscillations of the constant frequency of the radio or lower frequency range.

 As a nonlinear medium without an inversion center, quadratic nonlinear media, which include non-centrosymmetric crystals, can be used in this invention.

In particular, crystalline quartz is a quadratic nonlinear medium. The technology for growing artificial quartz crystals is well developed. In addition, crystalline quartz is transparent both for the initial optical radiation (optical transparency range of quartz: from λ ₁ = 0.15 μm to λ ₂ = 4.5 μm) and for microwave radiation. Therefore, crystalline quartz is a promising material for use in this invention when converting the energy of optical radiation with an arbitrary spectral width into the energy of vibrations or waves of the radio range, in particular the microwave range.

 As already noted, when using media with cubic non-linearity in this invention, it is necessary to have a constant electric field applied to this medium or, what is the same thing, a cubic non-linear medium must be placed in a constant electric field.

 In this case, this energy conversion proceeds much more efficiently if the frequency of one of the allowed transitions in a given medium is either close to or a multiple of the frequency of oscillations or waves generated in the medium whose energy is accumulated by resonators (the frequency of these oscillations or waves generated in the medium coincides with the resonant frequency of the resonators). In the case under consideration, there is a resonant increase in the cubic nonlinear susceptibility at a given frequency, which leads to an increase in the efficiency of this energy conversion.

 Nonlinear media without an inversion center, such as media with quadratic nonlinearity or media with cubic nonlinearity, placed in a constant electric (or magnetic) field, can additionally have negative absorption at the frequency of oscillations or waves generated in this medium and accumulated using resonators, t .e. have negative absorption at the resonant frequency of the resonators. Negative absorption is formed due to the creation of population inversion between the corresponding levels in the medium. In this case, in the present invention, oscillations or waves generated in a nonlinear medium will be further enhanced due to negative absorption caused by the activity of the medium at a given frequency.

In the present invention, in order to fulfill the condition of synchronism for harmonics of modulated optical radiation interacting in a nonlinear medium without a center of inversion and generated in the medium of vibrations or waves with a frequency that coincides with the resonant frequency of the resonators, the energy of which is accumulated using these resonators, a nonlinear medium can be used, size which L _о along the propagation direction of the modulated optical radiation does not exceed the length of the coherent interaction (or the length of the coherent aws) L _coh , i.e. L _о ≤ L _coh . The coherent interaction length L _coh is the maximum allowable size of a nonlinear medium without an inversion center, at which the phase incursion of all interacting harmonics of the modulated optical radiation and the oscillations or waves generated in this medium relative to each other does not exceed π (180 ^o ).

 In this case, the condition of synchronism will be satisfied without special measures, i.e. automatically.

Thus, the condition of synchronism can be fulfilled by choosing the size of the nonlinear medium L _о ≤ L _coh .

In particular, for harmonics of modulated laser radiation interacting in a nonlinear medium without an inversion center and oscillations or waves generated in this medium with a frequency that coincides with the modulation frequency, the coherent interaction length L _coh is determined by expression (2) (see Example 1).

To fulfill the condition of synchronism with the dimensions of a nonlinear medium without an inversion center along the propagation direction of the modulated optical radiation: L _о > L _coh , special measures must be taken. For this purpose, this nonlinear medium can be a set of noncentrosymmetric crystals, for example, quartz crystals, the size along the direction of propagation of the modulated optical radiation L _cr ≤ L _coh , touching each other or placed on the optical contact, and oriented relative to each other so that the waves of nonlinear polarization (occurring in crystals and being the source of oscillations or waves generated in the crystals of the radio or lower frequency range) each time passing We tested in a different crystal phase jump of π (180 ^o).

If such a nonlinear medium consists of m-crystals with sizes L _cr ≃ L _coh each, then the total medium size L _о , on which the synchronism condition will be fulfilled, will be equal to:
L _o = mL _cr >> L _co
High intensities of optical fields in nonlinear media without an inversion center with waveguide or fiber geometry, achieved at sufficiently low power levels of the initial optical radiation, as well as the possibility of controlling dispersion (i.e., the possibility of fulfilling the synchronism condition over a sufficiently extended interaction region in a given medium of size L _about> L _coh) allow, as compared with the volume extended nonlinear media, receive the same energy conversion efficiency at lower Q-factor D onatorov, or to increase the energy conversion efficiency for the same values Q of the resonator.

When the proposed method converts the energy of optical radiation into the energy of vibrations or waves of the microwave range, one volume microwave cavity can be used, and this nonlinear medium irradiated with modulated optical radiation can be placed inside this volume cavity of the microwave range, for example, a rectangular microwave cavity. In this case, the size of a nonlinear medium without an inversion center along the propagation direction of the modulated optical radiation coincides with the size of a rectangular microwave resonator, since the medium fills the resonator, and this size is usually smaller than L _coh . As a result, the condition of synchronism will be satisfied automatically without special measures.

 This nonlinear medium can be placed outside the microwave cavity, while the energy of electromagnetic waves or waves generated in the medium is removed from the medium and brought to the resonator, in which this energy is stored.

 In this case, to isolate this nonlinear medium and the resonator and prevent leakage of accumulated energy from the resonator back into the medium, you can use decoupling valve devices that provide unidirectional energy transfer, such as ferrite valves.

In the case under consideration, it is necessary to ensure that the synchronism condition is fulfilled for harmonics of modulated optical radiation and waves or waves generated in this medium and accumulated using a resonator that interact in a nonlinear medium without an inversion center. For this purpose, one can use a nonlinear medium of size L _о ≤ L _coh along the propagation direction of the modulated optical radiation, or a non-linear medium in the form of a set of noncentrosymmetric crystals of size L _cr ≤ L _coh each, placed on an optical contact and oriented relative to each other in the manner mentioned above.

 The geometry of a nonlinear medium without an inversion center in this case can have not only a volumetric extended character, but also a waveguide or fiber character.

 In order to reduce losses arising from the removal of a nonlinear medium without a center of inversion of the energy of oscillations or waves generated in this medium and the supply of this energy to the resonator, it is possible to use a volume microwave resonator with a capacitive gap in which this nonlinear medium is irradiated with an optical modulated radiation, for example a toroidal microwave cavity.

In this case, as well as in the previous ones, to fulfill the condition of synchronism between all the waves interacting in a given nonlinear medium, one can use a nonlinear medium without an inversion center of size L _о ≤ L _coh along the propagation direction of the modulated optical radiation, or a nonlinear medium without an inversion center , in the form of a set of noncentrosymmetric crystals of size L _cr ≤ L _coh each, placed on an optical contact and oriented relative to each other in the manner mentioned above, or use Inline media with fiber or waveguide geometry.

 When converting the energy of the initial optical radiation into the energy of the low-frequency part of the radio range, oscillatory circuits can be used as resonators, between the capacitor plates of which there is a nonlinear medium without an inversion center irradiated with modulated optical radiation.

The efficiency of this energy conversion depends on the quality factor of the resonator, and to obtain high conversion efficiency in the considered cases of accumulation of the converted energy using one resonator, resonators with a very high quality factor can be used, in particular, superconducting resonators with a quality factor of Q> 10 ⁹ (cryoelectronic superconducting resonators).

 To achieve high efficiencies of this energy conversion at low values of the Q factors of the resonators, one can use a sequential arrangement of several sections of a nonlinear medium along the propagation of the modulated optical radiation with resonators corresponding to these sections, which accumulate the energy converted in each section of the medium. In this case, the modulated optical radiation passes through the first section of the nonlinear medium without an inversion center with the corresponding resonator; as a result, using this method, a part of the energy of the modulated optical radiation is converted into electromagnetic energy of the radio or lower frequency range. The remaining unconverted part of the energy of the modulated optical radiation undergoes further conversion in the next section of the nonlinear medium (located along the propagation of the modulated optical radiation) with the corresponding resonator, in which the converted energy is accumulated in the above manner, etc. The sizes of sections of nonlinear media without an inversion center in the case under consideration are selected for reasons of synchronism for the harmonics of the modulated optical radiation interacting in the medium and for the data of the vibrations or waves generated in the medium whose energy is stored using the resonator.

 High values of the efficiency of this energy conversion at low values of the Q factor of the resonators can also be achieved using multiple passage of modulated optical radiation along a closed loop through the same section of a nonlinear medium without an inversion center, and the accumulated converted energy can be stored in the resonator corresponding to this section in the above manner.

 In this case, the multiple passage of modulated optical radiation along a closed loop through the same section of a nonlinear medium can be achieved using optical elements such as mirrors, prisms, optical fibers, etc.

 To store the converted energy, several resonators combined in cascades can be used with the same resonant frequency equal to or a multiple of the modulation frequency and coinciding with the frequency of these oscillations or waves generated in a nonlinear medium without an inversion center. A nonlinear medium without an inversion center can be located both inside the cavity of the first cascade and outside it. In the case under consideration, the energy of oscillations or waves generated in a given medium is accumulated in the first low-Q resonator (resonator of the first cascade). Then, the converted energy stored in the first resonator is supplied to the second resonator (the resonator of the second stage) with the same resonant frequency, where the accumulation of the converted energy of the radio or lower frequency range will continue. From the resonator of the second stage, the stored converted energy can be supplied to the resonator of the third stage, etc. To prevent the influence of each subsequent resonator on the previous one, isolation valves can be used that transmit converted energy in only one direction from the resonator of the previous stage to the resonator of the subsequent stage, for example, ferrite valves.

 Some nonlinear media without an inversion center, for example, crystalline quartz, additionally have pronounced electro-optical properties. In this case, the modulation of optical radiation and the generation of oscillations or waves of the radio or lower frequency range can be carried out in the same nonlinear medium without an inversion center. That is, the same given nonlinear medium can be due to the electro-optical properties a medium of an electro-optical modulator that modulates the initial optical radiation in phase (or frequency), in particular, a medium for an electro-optical traveling wave modulator, as well as a medium in which oscillation occurs or waves of the radio or lower frequency range due to the presence of the corresponding nonlinear properties. In this case, the processes of modulation of optical radiation and generation of oscillations or waves of the radio or lower frequency range can occur in parallel.

 Moreover, if a nonlinear medium without an inversion center, for example, crystalline quartz, has electro-optical properties, nonlinearity, and piezoelectric properties, then all steps of this method of energy conversion can be carried out in one medium, namely: modulation of optical radiation, generation of oscillations or waves of radio or lower frequency range and the accumulation of the converted energy of these oscillations or waves due to the piezoelectric properties of the medium when the frequency of the generated oscillations or waves coincides, The energy of which should be accumulated with the natural frequency of mechanical vibrations of a given medium. In this case, the same medium due to the electro-optical properties can be a medium of an electro-optical modulator that modulates optical radiation in phase (or frequency) in the above manner, a medium in which oscillations or waves of the radio or lower frequency range are generated due to the corresponding nonlinear properties and the environment of the piezoelectric resonator, in which the accumulation of converted energy can be carried out. In this case, the processes of modulation, generation and accumulation of converted energy can occur in parallel.

 The present invention allows the amplification, generation and multiplication of frequencies of high-frequency electromagnetic waves, in particular, microwave oscillations.

 To amplify using the proposed method a high-frequency signal, which is high-frequency electromagnetic waves generated from an independent high-frequency generator, it is necessary to modulate the initial optical radiation with these oscillations, while the resonant frequency of the resonators accumulating the converted energy must coincide with the modulation frequency, i.e. with the frequency of amplified initial oscillations. When the stored converted energy is removed from the resonator, high-frequency oscillations are obtained that are more powerful than the original ones of the same frequency, i.e. amplification of the initial high-frequency oscillations, which modulate the optical radiation, occurs.

 In this case, the amplification of high-frequency electromagnetic waves, which modulate optical radiation, occurs due to the conversion of the energy of optical radiation into the energy of high-frequency electromagnetic waves with a frequency equal to the modulation frequency and coinciding with the resonant frequency.

 For self-excitation, i.e. To generate electromagnetic high-frequency oscillations, in particular, microwave oscillations, in the case of amplification of oscillations described above, it is sufficient to use positive feedback between the resonator, in which the converted energy is accumulated (by the output of the amplification circuit) and vibrations modulating optical radiation (by the input) modulator or input gain circuit). To this end, part of the energy converted and stored in the resonator is transmitted to the input of the modulator to modulate the initial optical radiation, i.e. use part of the converted energy to form a modulating signal.

 To multiply frequencies, i.e. increase in an integer number of times the frequency of high-frequency oscillations, in the above case of amplification of electromagnetic oscillations, the resonant frequency of the resonator is selected multiple of the modulation frequency. In this case, using the proposed conversion method, the energy of optical radiation is converted into the energy of high-frequency oscillations with a frequency that is a multiple of the modulation frequency and coincides with the resonant frequency. As a result, when the accumulated converted energy is removed from the resonator, electromagnetic oscillations are obtained with a frequency an integer number of times higher than the frequency of the initial electromagnetic oscillations, which modulate the optical radiation, i.e. multiply frequencies.

 In the invention, laser radiation can be used as the initial optical radiation. Such characteristics of laser radiation as low angular divergence, high radiation power when using high power lasers make laser radiation effective for this energy conversion.

 In the present invention, it is possible to use both radiation from continuous-wave and pulsed lasers.

- циклическая частота модуляции.When using pulsed laser radiation, it is necessary that the pulse duration T _{i of the} laser radiation substantially exceeds the period of modulating oscillations of a constant frequency T _mod (T _i > T _mod ), where

- cyclic modulation frequency.

 As the initial optical radiation in the proposed method of energy conversion can be used solar radiation.

 This invention allows the conversion of the energy of solar radiation on the Earth's surface into the energy of electromagnetic waves or waves of the radio or lower frequency range, in particular into the electromagnetic energy of the microwave range, as well as into alternating or direct current energy.

 Another important particular case is the conversion of the energy of solar radiation into electromagnetic energy of the radio or lower frequency range, in particular the microwave range, by the proposed method in a space object placed, for example, in geosynchronous (or solar-synchronous) orbit, and transferring the result of the conversion energy of microwave radiation to the Earth or to other space objects, where it is captured by a special antenna and can be converted further using rectifier devices, for example Microwave rectifiers into electrical energy of direct or alternating current.

 In this case, to transfer the converted energy to the Earth, the modulation frequency of solar radiation is selected so that the resonance frequency of one or more resonators, equal to or a multiple of the modulation frequency, is within the frequency range of the transparency of the atmosphere. As a result, the frequency range of the converted microwave energy will be within the frequency range of the transparency of the atmosphere and the transfer of converted microwave energy to the Earth will occur with minimal loss.

 In order to increase the efficiency of the operation of this method of energy conversion and reduce the requirements for the Q factors of resonators during energy conversion and storage, auxiliary optical systems can be used to focus optical radiation and give this radiation after modulation a predetermined shape when it propagates in a nonlinear medium without an inversion center.

 To increase the energy of the converted optical radiation, the energy of several optical radiation streams is simultaneously converted by the proposed method simultaneously (for example, using several optical radiation modulators, several sections of nonlinear media without an inversion center with resonators corresponding to these sections), all channels for transmitting converted energy from each stream of optical radiation (these channels can be coaxial cables or waveguides) one common channel (for example, a waveguide or coaxial cable) for transmitting the resulting converted energy from all streams. In particular, the simultaneous conversion of the energy of several streams of solar radiation by the proposed method allows this conversion of solar energy from a larger area, i.e. allows you to increase the energy of solar radiation to be converted.

 The drawings show examples of the conversion of the energy of optical radiation with an arbitrary spectral width into the energy of electromagnetic waves or waves of the radio or lower frequency range of the proposed method.

 In FIG. 1 shows a scheme for converting laser radiation energy into microwave energy based on the present invention using a volume microwave cavity in which a quartz crystal is placed; figure 2 - diagram of the conversion of laser radiation energy into microwave energy using the invention, in which a quartz crystal is located outside the microwave resonator; in FIG. 3 is a diagram of the conversion of laser energy by the proposed method into microwave energy using a toroidal resonator of the microwave range, in the capacitive gap of which a quartz crystal is placed; figure 4 is a diagram of the conversion of laser radiation energy into microwave energy using several sections of a nonlinear medium without an inversion center (several quartz crystals) with resonators corresponding to these sections of the medium (quartz crystals), based on this invention; figure 5 is a diagram that converts the energy of laser radiation into microwave energy by repeatedly passing the modulated laser radiation in a closed loop using the invention, where: 1 - a beam of laser radiation; 2 - modulator; 3 - modulated laser radiation; 4, 4 '- quartz crystals; 5, 5'- microwave electromagnetic resonators; 6 - contact deposited on the surface of a quartz crystal; 7 - coaxial cable (or waveguide); 8 - translucent mirror; 9, 10, 11 - mirrors.

 Example 1. Converting the energy of continuous-wave laser radiation into microwave electromagnetic energy.

In figure 1, the original continuous-wave laser radiation (1) with a cyclic frequency ω _o using a modulator (2) is modulated in phase (or frequency) by harmonic oscillations of the constant frequency of the microwave range.

 Modulated laser radiation (3), which is irradiated with crystalline quartz (4), propagates in a transparent quartz crystal placed in the resonator (5).

 In the circuit of FIG. 1, a cavity rectangular microwave cavity resonator with a resonant frequency matching the modulation frequency is used as a resonator (5).

 A quadratic nonlinear medium, namely, a quartz crystal, is used as a nonlinear medium without an inversion center.

 The optical transparency range of crystalline quartz is in the range of wavelengths λ = 0.15 - 4.5 microns, in addition, quartz is transparent for electromagnetic waves in the microwave range.

,
где n_Ω - коэффициент преломления кристалла кварца на частоте модуляции,
Ω - циклическая частота модуляции,
С - скорость в вакууме.Since the resonant frequency of the resonator coincides with the modulation frequency (in this example, the resonant frequency is the frequency of the main oscillation of the resonator), the size of the resonator L _о along the propagation direction of the modulated laser radiation, which coincides with the size of the quartz crystal (4) filling this resonator, is determined as follows :

,
where n _Ω is the refractive index of the quartz crystal at the modulation frequency,
Ω is the cyclic modulation frequency,
C is the speed in vacuum.

As you know, the spectrum of the phase modulated in phase (or frequency) laser radiation with the frequency ω _{o in the} above manner turns out to be discrete, symmetric with respect to ω _o and containing many side frequencies of the form ω _n = ω _o ± nΩ, where n = 1, 2, 3, .. with amplitudes distributed over Bessel functions.

Thus, with phase (or frequency) modulation by harmonic oscillations of the laser radiation, the carrier frequency ω _o (laser frequency before modulation) corresponds to the frequency spectrum of the modulated laser radiation, many frequencies equally spaced from each other by the modulation frequency Ω.

Therefore, the propagation of laser radiation modulated by phase (or frequency) in a nonlinear medium without an inversion center (in this case, in a quartz crystal) can be considered as the propagation of a set of harmonics (spectral components) of the modulated radiation, i.e. sets of harmonic waves with frequencies ω _n = ω _o ± nΩ, where n = 1, 2, 3 ... and amplitudes distributed over the Bessel functions.

,
где n_Ω - коэффициент преломления кристалла кварца на частоте модуляции,
Ω - циклическая частота модуляции,
n_ωгрн - коэффициент преломления на нижней границе оптического диапазона кристалла кварца.It can be shown that the length of the coherent interaction (coherence length) L _coh (L _coh is the maximum distance in the quartz crystal at which the phase incursion for all harmonics of modulated radiation and generated microwave waves interacting in this crystal with a frequency coinciding with the modulation frequency, with respect to each other does not exceed π (180 ^o )) is described by the expression:

,
where n _Ω is the refractive index of the quartz crystal at the modulation frequency,
Ω is the cyclic modulation frequency,
n _ωgrn is the refractive index at the lower boundary of the optical range of a quartz crystal.

From a comparison of expressions (1) and (2), it is easy to obtain that L _о <L _coh .

 Therefore, in this case, the condition of synchronism for all interacting waves in a quartz crystal is automatically satisfied without special measures, as a result of which the interaction data are in phase.

 Thus, in the circuit of Fig. 1, the modulated laser radiation (3), which is irradiated with a quartz crystal (4), begins to propagate in this transparent crystal, due to the nonlinearity of the properties of which in-phase interactions between the harmonics of the modulated radiation begin to occur, and as a result lasing in this crystal of an electromagnetic wave of the microwave range at a frequency that coincides with the modulation frequency, i.e. microwave generation occurs. The generation of microwave radiation occurs due to the beat of harmonics of modulated laser radiation in a quartz crystal, nonlinear polarization waves arise at the difference frequency, which coincides with the modulation frequency of the microwave range, which are the source of the generated microwave radiation (in this case, the source of the generated electromagnetic microwave wave range with a frequency equal to the modulation frequency).

 With the further propagation of modulated laser radiation in a quartz crystal, in-phase interactions between the harmonics of the modulated radiation and the generated microwave radiation will occur, which will lead to a further increase in the power of the generated microwave radiation with a frequency that coincides with the modulation frequency, i.e. The conversion of laser radiation energy into microwave energy will occur.

 To increase the efficiency of this energy conversion in the circuit in figure 1, the converted microwave energy is stored using a rectangular microwave resonator (5) with a resonant frequency coinciding with the modulation frequency, and the converted energy is accumulated in this case as follows.

 When the modulated laser radiation passes along the Z axis through the quartz crystal, the microwave radiation generated in it also propagates along the Z axis. Then, this microwave radiation is reflected from the cavity wall and propagates in the opposite direction, with no interaction with the harmonics of the modulated radiation. Reflected from the second cavity wall, microwave radiation with a frequency equal to the modulation frequency is in phase with itself and with harmonics of the modulated radiation, and the process of generating microwave radiation under the condition of synchronism for all waves interacting in a quartz crystal will be repeated. Thus, microwave radiation with a frequency equal to the modulation frequency, periodically reflected from the cavity walls, will pass through the quartz crystal repeatedly, amplifying each time. As a result, the energy of microwave radiation generated in the quartz crystal (4) will accumulate in the high-Q cavity (5) for a long time.

Denote the Q factor of the resonator (5) by Q, and the amplitude of the microwave radiation generated in the quartz crystal with a frequency equal to the modulation frequency in one pass is through U ₀ . Obviously, the amplitude U _{Σ of the} microwave field accumulated over Q passes in the resonator is determined by:
U _Σ = Q • U _o (3)
The higher the Q factor of the resonator (5), the more efficiently the given energy conversion proceeds, and the greater the efficiency value of this transformation.

 Let us dwell on the requirements for the stability of the modulation frequency in this method of energy conversion. Obviously, the coherence time of modulating oscillations should exceed the time during which the converted energy accumulates in the resonator (5).

,
где ΔΩ - ширина полосы частоты модуляции,
Q - добротность резонатора
В качестве модуляторов, осуществляющих модуляцию по фазе (или частоте) исходного лазерного излучения (1) гармоническими колебаниями постоянной частоты СВЧ диапазона могут использоваться электрооптические модуляторы, работающие на эффекте Поккельса.As a result, for the energy conversion circuit of FIG. 1 easy to get:

,
where ΔΩ is the modulation frequency bandwidth,
Q - Q factor of the resonator
Electro-optical modulators operating on the Pockels effect can be used as modulators that modulate in phase (or frequency) the initial laser radiation (1) by harmonic oscillations of the constant frequency of the microwave range.

 This modulator can also be a mirror oscillating with a constant frequency of the microwave range. For this purpose, the mirror is either directly mounted on the end of the piezoelectric transducer, or the reflective coating is sprayed onto the end of the piezoelectric transducer. When an electromagnetic signal with a constant frequency of the microwave range is applied to the piezoelectric transducer, it begins to vibrate with this frequency together with the mirror, or with a mirror coating due to the inverse piezoelectric effect. The initial laser radiation (1) reflected from such a mirror oscillating at a constant frequency in the microwave range is modulated in the above manner.

Example 2. The same as in example 1, only to increase the efficiency of this energy conversion as a microwave resonator (5) use a superconducting microwave cavity (cryoelectronic superconducting resonator). These resonators have a very high Q factor Q (Q> 10 ⁹ ) in the microwave range and, as calculations show, in this case the efficiency of the energy conversion under consideration can reach 90% even at relatively low powers (of the order of one watt) of the initial continuous-wave laser radiation.

 Example 3. The same as in example 1, only as the initial laser radiation using pulsed laser radiation, provided that the duration of the laser pulse substantially exceeds the period of modulating harmonic oscillations of the constant frequency of the microwave range.

 Example 4. The same as in example 1, only the initial laser radiation (1) is modulated in amplitude by oscillations of a constant frequency of the microwave range of a rectangular shape (ie, amplitude modulation is carried out by periodic non-harmonic oscillations of a constant frequency).

 Example 5. The same as in example 1, only the microwave energy converted and stored in the resonator (5) is removed from the resonator, and microwave energy is transmitted through the free space using a radiating (transmitting) antenna.

 Example 6. The same as in example 1, only for conversion into energy of low-frequency electromagnetic waves of industrial or arbitrarily low frequency (that is, to convert to energy of alternating current of industrial frequency or into direct current energy) converted and stored in the resonator (5) the microwave energy is removed from the resonator and, using a microwave rectifier, these low-frequency electromagnetic waves are converted into energy.

 The conversion efficiency of modern microwave rectifiers (vacuum or semiconductor), which are converters of microwave energy into direct or alternating current energy, reaches 80-90%.

 The resulting conversion efficiency of the proposed method, the laser radiation energy into direct or alternating current energy can reach 70-80% when using superconducting resonators with high quality factor (cryoelectronic superconducting resonators).

 Example 7. The same as in example 1, only as the initial optical radiation (1) to be converted, use solar radiation.

 In this case, the conversion of solar radiation energy into electromagnetic energy of the microwave range is carried out.

 Calculations show that in this example, when using a superconducting resonator (cryoelectronic superconducting resonator) as a resonator (5) with high Q factor, the efficiency of converting the energy of solar radiation into electromagnetic energy of the microwave range can reach 70%.

 Example 8. The same as example 6, only as the initial optical radiation (1) to be converted, use solar radiation.

 In this case, the energy of solar radiation is converted into energy of direct or alternating current of industrial frequency.

 Calculations show that when superconducting resonators are used, the energy conversion efficiency in this example can reach 50-60%.

 Example 9. The same as in example 7, only the conversion of the energy of solar radiation into electromagnetic energy of the microwave range is performed on a space object placed in a geosynchronous orbit, while the converted and stored in the resonator (5) microwave energy is removed from the resonator and using The transmitting antenna transmits microwave energy to Earth, where the microwave radiation is captured by the receiving antenna. Next, using microwave rectifiers, the final conversion to electrical energy of direct or alternating current of industrial frequency is carried out.

 In this case, to transfer the converted microwave energy to the Earth with the least loss, the modulation frequency of solar radiation is selected so that the resonant frequency of the resonator (5) (and, therefore, coinciding with the resonant frequency, the frequency of the converted microwave radiation transmitted to the Earth) is equal to the modulation frequency , was in the frequency range of atmospheric transparency.

 It should be noted that the implementation of the conversion of solar radiation energy into microwave energy on a space object located in a geosynchronous orbit will ensure the continuous transfer of converted microwave energy to the Earth, since this space object is continuously or almost continuously illuminated by the Sun. In addition, the density of solar radiation in space is greater than on Earth.

 Example 10. The same as in example 7, only in this case they use optical systems (lenses, spherical mirrors, etc.) both for concentration (focusing) of the initial solar radiation and for giving the beam of modulated solar radiation a predetermined shape , in this case, the shape of a narrow parallel beam, when it propagates in a quartz crystal.

 The use of optical systems improves the efficiency of this energy conversion.

 Example 11. The same as in example 7, only they convert the proposed method the energy of several streams of solar radiation simultaneously using several circuits similar to the scheme in figure 1, each of which converts the energy of one of the streams of solar radiation.

 Moreover, all channels for transmitting converted microwave energy from each of the solar radiation streams (in this example, all coaxial cables that transmit the converted and stored microwave energy in the resonators) are switched into one common channel (common coaxial cable), through which the resulting converted Microwave energy from all streams of solar radiation.

 Next, the resulting converted energy from several streams of solar radiation is either supplied to a radiating microwave antenna for the purpose of further wireless transmission of the converted microwave energy through free space, or fed to microwave rectifiers for conversion into electrical energy of direct or alternating current.

 The simultaneous conversion of energy from several streams of solar radiation, followed by switching the transmission channels of the converted microwave energy from each of the streams into one common channel for transmitting the resulting converted microwave energy from all streams, allows this conversion of solar energy to microwave energy from a larger area, i.e. allows to increase the energy of solar radiation to be converted.

 Example 12. The same as in example 1, only a quartz crystal is placed outside the resonator, while the converted electromagnetic energy of the microwave radiation generated in the crystal is fed to the resonator in which this converted energy is stored.

In FIG. Figure 2 shows a quartz crystal (4) of size L ≤ L _coh (see expression (2) in Example 1), in which modulated laser radiation (3) propagates when it is irradiated. Microwave radiation generated in a crystal with a frequency that coincides with the modulation frequency, is applied to the chip (6) and a coaxial cable (7) (or waveguide) applied to the crystal, and is transferred to the microwave cavity (5), tuned only to the modulation frequency (i.e. resonant frequency of the resonator coincides with the modulation frequency).

If we denote the amplitude of the microwave radiation generated in the quartz crystal by U ₀ , then the amplitude U _{Σ of the} forced microwave oscillations established in the cavity will be Q times the amplitude of the acting signal, in this case, the amplitude U _{0 of the} generated microwave radiation. Therefore, U _Σ = QU ₀ , where Q is the Q factor of the resonator.

 Example 13. The same as in example 12, only to prevent the accumulated converted energy from leaking from the microwave cavity (5) back to the quartz crystal (4), i.e. To isolate the medium and the resonator, ferrite gates are additionally used, which transmit the microwave radiation generated in the crystal in only one direction - from the quartz crystal (4) to the resonator (5).

Example 14. The same as in example 12, only instead of a quartz crystal (4), size L _о ≤ L _coh , use an extended quadratic nonlinear medium consisting of a set of quartz crystals in contact with each other, the sizes of L _{cr of} which along the direction of propagation modulated laser radiation is less than or equal to the coherent interaction length L _coh (L _cr ≤ L _coh ), while the quartz crystals are oriented relative to each other so that the waves of nonlinear polarization (arising in the crystals due to beats on the difference part equal to the frequency of modulation of the harmonics of the propagating modulated laser radiation), each time passing through another crystal, a phase jump of π (180 ^° ) was experienced.

If such a quadratic nonlinear medium consists of m-crystals, and the size of each crystal is L _cr к L _coh , then the total medium size L _о , on which the synchronism condition will be fulfilled for all interacting waves, will be equal to mL _coh , i.e. L _o = mL _coh > L _coh .

 As a result, to achieve the same efficiency as in Example 12, lower-quality resonators are required.

 Example 15. The same as in example 12, but instead of a quartz crystal (4), an optical fiber made of single-crystal quartz is used (see FIG. 2), i.e., a quartz crystal with fiber geometry is used.

In this case, even at sufficiently low power levels of the initial laser radiation, high optical fields are achieved due to the fiber geometry of the quartz crystal, which increases the efficiency of this energy conversion. In addition, due to this crystal geometry, it becomes possible to control dispersion, i.e. the possibility of fulfilling the condition of synchronism for all interacting waves in an optical fiber from a quartz single crystal at a distance L _o > L _coh .

 Example 16. The conversion of laser radiation energy into microwave energy with a frequency that matches the doubled (multiple) modulation frequency.

The same as in example 12, only the resonant frequency of the resonator (5) coincides with the doubled modulation frequency, i.e. the resonator is tuned to a frequency multiple of the modulation frequency, namely, twice the modulation frequency. In addition, to fulfill the condition of synchronism between the harmonics of the modulated radiation and the electromagnetic microwave wave generated in the quartz crystal with a frequency equal to twice the modulation frequency, the size of the quartz crystal L _{о is} chosen to be less than or equal to the length of the coherent interaction in the case under consideration. As a result, in the resonator (5) tuned to a double modulation frequency, the microwave waves generated in the crystal will accumulate with a frequency equal to the double modulation frequency.

 The length of the coherent interaction in this case, depending on the doubled modulation frequency, is two times less than the length of the coherent interaction defined by expression (2) in Example 1.

The generation of microwave radiation (microwave waves) with a frequency equal to twice the modulation frequency in a quartz crystal occurs due to the appearance of a nonlinear polarization in the crystal wave at a difference frequency equal to twice the modulation frequency. These non-linear polarization waves, which are the source of microwave radiation generated in the crystal with a double modulation frequency, arise due to beats between the harmonics of the modulated radiation with frequencies ω _o and ω _o -2Ω, ω _o -2Ω and ω _o -4Ω, etc., where ω _o is the cyclic frequency of the initial laser radiation, Ω is the cyclic modulation frequency.

 In the example under consideration, efficient conversion to microwave energy with a double modulation frequency occurs due to the fact that in a microwave resonator tuned to this frequency, energy is generated in the microwave radiation generated in a quartz crystal only with a double modulation frequency, while for this Microwave radiation, it is necessary to fulfill the condition of synchronism for the interacting harmonics of modulated radiation and the generated microwave radiation with a double modulation frequency.

Example 17. The same as in example 12, only as a nonlinear medium without an inversion center, a cubic nonlinear medium placed in a constant electric field, namely ammonia (molecular gas NH ₃ ), in the presence of a constant electric field is used.

 In this case, to a transparent glass flask filled with ammonia, a constant electric field is applied using electrodes.

 Example 18. The same as in example 17, only the modulation frequency is chosen equal to or close to the natural frequency of the transition between the levels of ammonia, which lies in the microwave range and is equal to ν = 23870 MHz.

 In this case, due to the resonant increase in the cubic nonlinear susceptibility of a given medium, the energy conversion efficiency increases.

Example 19. The same as in example 18, only additionally using standard methods create a population inversion between the corresponding levels of ammonia (NH ₃ ) with an eigenfrequency of the transition ν = 23870 MHz, for example, using an electric discharge or using a time-constant but nonuniform in the space of an electric or magnetic field.

 In this case, during the propagation of laser modulated radiation, the microwave radiation generated in a given nonlinear medium with a frequency equal to the modulation frequency and coinciding with this transition frequency will be further enhanced due to the presence of negative absorption caused by the activity of the medium at this frequency (i.e., due to the presence of population inversion between these levels).

 Example 20. The same as in example 12, only for the accumulation of converted energy, several resonators with the same resonant frequency equal to the modulation frequency are used, cascaded through ferrite gates that transmit the converted and stored microwave energy in only one direction from resonator of the previous cascade to the resonator of the subsequent cascade. To do this, the converted energy stored in the resonator (5) of the first stage, using a coaxial cable or waveguide, is fed through a ferrite gate to the next resonator with the same resonant frequency (resonator of the second stage), in which the process of accumulation of the converted energy continues. From the resonator of the second stage, the accumulated converted microwave energy can be supplied to the resonator of the third stage, etc.

 In this case, ferrite valves are used to prevent the influence of each subsequent resonator on the previous one.

 Example 21. The same as in example 12, only as a modulator (2) use the electro-optical modulator of the traveling wave, with which modulate the initial laser radiation in phase by harmonic oscillations of the constant frequency of the microwave range. In this case, one part of the quartz crystal (4), due to its electro-optical properties, is the medium of the traveling wave electro-optical modulator, and due to the presence of nonlinear properties in the same quartz crystal, microwave radiation (microwave waves) is generated with a frequency equal to the modulation frequency, whose energy is supplied to the resonator (5) and accumulate in it.

 In this example, the modulation of optical radiation and the generation of microwave radiation is carried out in the same nonlinear medium (quartz crystal).

 Example 22. The same as in example 21, only the energy storage of the microwave waves generated in the crystal with a frequency equal to the modulation frequency is carried out using a quartz resonator due to the piezoelectric properties of the quartz crystal. For this, the modulation frequency is selected so that the frequency of the microwave waves generated in the quartz crystal, equal to the modulation frequency, also coincides with the natural frequency of the mechanical vibrations of the quartz crystal.

 In this case, all the steps of this method of energy conversion (modulation of optical radiation, generation of microwave waves and the accumulation of converted microwave energy) are carried out in the same medium (in this example, in crystalline quartz) due to the presence of electro-optical, non-linear and piezoelectric properties in this Wednesday.

 Example 23. The same as in example 12, only to reduce losses arising from the removal of the generated microwave radiation from the quartz crystal and its supply to the resonator, a microwave cavity with a capacitive gap is used in which this quartz crystal is irradiated with laser radiation. .

In FIG. 3, a quartz crystal (4) of size L _о ≤ L _coh , in which modulated laser radiation propagates (3), is placed in the capacitive gap of the toroidal resonator (5) with a resonant frequency that coincides with the modulation frequency lying in the microwave range.

 Example 24. The conversion of the energy of the original laser radiation into electromagnetic energy of the low-frequency part of the radio range.

The same as in example 23, only for converting the low-frequency part of the radio range into electromagnetic energy as a resonator (5), an oscillatory circuit is used, between which a quartz crystal (4) of size L _о ≤ L _coh is placed. In this case, the resonant frequency of the oscillatory circuit coincides with the modulation frequency, which is located in the low-frequency part of the radio range.

 Example 25. The implementation of the amplification of electromagnetic microwave signals using the proposed method of energy conversion.

 The same as in example 23, only to amplify the microwave signal generated from an independent microwave generator and representing electromagnetic microwave oscillations, these amplified microwave oscillations modulate the initial laser radiation (1) using a modulator (2) in the above manner (see Fig. 3), for which amplified microwave oscillations are fed to the input of the modulator. In this case, the resonant frequency of the resonator (5), which accumulates the converted microwave energy, coincides with the modulation frequency, i.e. with the frequency of amplified initial vibrations that modulate laser radiation.

 When the converted and stored energy is removed from the resonator, high-frequency oscillations are obtained that are more powerful than the original ones and with the same frequency. The amplification of the initial microwave oscillations that modulate the laser radiation occurs.

 Amplification occurs by converting the energy of laser radiation into the energy of microwave oscillations of a given frequency.

 Example 26. The implementation of the generation of electromagnetic microwave signals. The same as in example 25, only for self-excitation, i.e. To generate electromagnetic microwave oscillations, using the feedback circuit, a positive feedback is generated between the resonator (5), in which the converted energy is accumulated (by the output of the amplification circuit) and the input of the modulator (2) (by the input of the amplification circuit).

 As you know, feedback refers to the transmission of signals from the output of the circuit to its input, while generation occurs during the implementation of positive feedback.

 In this example, to provide positive feedback, part of the energy converted and stored in the resonator (5) is transmitted to the input of the modulator by the feedback circuit to modulate the initial optical radiation.

 Example 27. The implementation of the multiplication of frequencies of microwave signals.

Same as in example 25, only for frequency multiplication, i.e. to increase the frequency of microwave oscillations by an integer number of times, the resonant frequency of the resonator (5) is selected to be a multiple of the modulation frequency, i.e. _Res Ω = nΩ, where n - an integer characterizing the multiplicity.

 In this case, the laser energy is converted into microwave energy with a frequency multiple of the modulation frequency.

 An effective conversion to microwave energy with a frequency that is a multiple of the modulation frequency occurs due to the fact that in the microwave cavity tuned to this frequency, energy is generated in the microwave field generated in a quartz crystal only with a frequency that is a multiple of the modulation frequency, while for efficient generation in a crystal of a given microwave field satisfies the condition of synchronism for the interacting harmonics of the modulated radiation and the generated microwave field with a frequency multiple of the modulation frequency.

As in example 25, in order to fulfill the condition of synchronism, the size of the quartz crystal L _{о is} chosen smaller or equal to the length of the coherent interaction L _coh (L _o ≤ L _coh ). However, in the case under consideration, the length of the coherent interaction depends on a given frequency, a multiple of the modulation frequency, and is n-times less than the length of the coherent interaction defined by expression (2) in Example 1.

 As a result, when the converted and stored microwave energy is output from the resonator, electromagnetic microwave oscillations are obtained with a frequency an integer number of times higher than the frequency of the original electromagnetic microwave oscillations that modulate laser radiation, i.e. multiply frequencies.

 Example 28. Implementation of the conversion of laser radiation energy into electromagnetic energy of the microwave range using several sections of a nonlinear medium without an inversion center with resonators corresponding to these sections.

 To carry out this conversion, a sequential arrangement of several sections of a nonlinear medium without an inversion center with resonators corresponding to these sections of resonators accumulating the energy converted in each of the sections of this medium is used in the course of propagation of the modulated laser radiation.

 In Fig. 4, several quartz crystals (4), (4 ') with corresponding resonators (5), (5') are arranged sequentially along the propagation of the modulated laser radiation.

In this case, volumetric toroidal resonators with the same resonant frequencies that coincide with the modulation frequency of the microwave range are used as microwave resonators. The sizes L _{о of} quartz crystals (4), (4 ') along the propagation of the modulated laser radiation are the same and are selected based on the fulfillment of the synchronism condition for harmonics interacting in the crystals of the modulated laser radiation and the generated microwave radiation with a modulation frequency. In figure 4, L _o ≤ L _coh , where L _coh is determined from the expression (2) in example 1.

 Modulated laser radiation (3) passes through a quartz crystal (4) located in the capacitive gap of the toroidal resonator (5), as a result of which a part of the modulated laser radiation is converted to microwave energy with its subsequent accumulation.

 The remaining non-converted part of the energy of the modulated laser radiation undergoes further conversion to microwave energy on the next quartz crystal (4 ') located in the capacitive gap of the resonator (5'), in which the converted energy is accumulated, etc.

 Obviously, the use of several sections of nonlinear media without an inversion center with resonators corresponding to these sections at the same efficiency values as in Example 23 allows us to reduce the requirements for the Q factor of the resonators, or to increase the efficiency of this energy conversion at the same Q factors.

 Example 29. The implementation of the conversion of laser radiation energy into microwave energy using multiple passage of modulated laser radiation in a closed loop.

 High values of the efficiency of the proposed energy conversion at low values of the Q factors of the resonators can also be achieved using multiple passage of the modulated optical radiation along a closed loop through the same section of a nonlinear medium without an inversion center, and the accumulated converted energy will be produced in the corresponding resonator section in the above manner .

In FIG. 5 quartz crystal (4), _of size L ≤ L _coh (sm.vyrazhenie (2) in Example (1)) to the capacitive gap corresponding toroidal microwave resonator (5), both located in the optical ring resonator composed of mirrors ( 9), (10), (11) and a translucent mirror (8).

 In this case, using a translucent mirror (8) and mirrors (9), (10), (11) an optical ring resonator, multiple modulated laser radiation is transmitted through this crystal (4) with the corresponding microwave resonator (5), whose resonant frequency is modulation frequency, and the energy of the quartz generated in the crystal at each pass of the microwave radiation is accumulated in the toroidal resonator (5), which leads to an increase in the efficiency of this transformation compared to a single passage.

Example 30. The same as in example 29, only for multiple passage of the modulated laser radiation in a closed loop, a Fabry-Perot optical resonator is used, between two mirrors of which a quartz crystal of size L _o ≤ L _coh with a corresponding toroidal microwave resonator is placed whose resonant frequency is equal to the modulation frequency.

 In this case, using two flat mirrors of an open optical resonator (Fabry-Perot resonator), the modulated laser radiation is repeatedly transmitted through a given quartz crystal located in the capacitive gap of the toroidal microwave resonator, while at each pass the converted microwave energy will accumulate in this microwave resonator.

Claims (31)

 1. A method of converting the energy of optical radiation with an arbitrary spectral width into the energy of electromagnetic waves or waves of the radio or lower frequency range, comprising irradiating with optical radiation a medium in which the energy of optical radiation is converted, characterized in that the optical radiation is modulated in time by oscillations of a constant frequency radio or lower frequency range so that in the frequency spectrum of the modulated optical radiation of each carrier frequency and similar unmodulated optical radiation corresponded to many frequencies equally spaced from each other by the modulation frequency, a nonlinear medium without an inversion center is used as the medium, in which the energy of the modulated optical radiation is converted in the form of electromagnetic waves or waves of the radio or lower frequency range, and which transparent both for the frequencies of the optical range, and for the frequencies of electromagnetic waves generated in it or waves of radio or lower frequency range, the converted energy generated in this nonlinear medium without a center of inversion of electromagnetic waves or waves of the radio or lower frequency range is accumulated using one or more electromagnetic resonators, the resonant frequency of which coincides with the frequency of the generated electromagnetic waves or waves of the radio or lower frequency range and equal to or a multiple of the modulation frequency, while the condition of synchronism for interacting in a given nonlinear medium without cent Inversion of harmonics of modulated optical radiation and generated electromagnetic waves or waves of the radio or lower frequency range, the energy of which is accumulated using one or more resonators.  2. The method according to claim 1, characterized in that they convert the energy of electromagnetic waves or waves of the microwave or lower frequency range and transmit the converted and stored energy through the emitting antenna through the free space.  3. The method according to claim 1, characterized in that the energy is converted into electromagnetic waves or waves of the microwave or lower frequency range, then the converted and stored energy of the microwave or lower frequency range is additionally converted using rectifiers to low-frequency electromagnetic energy of industrial frequency or any arbitrarily low frequency.  4. The method according to claim 1, characterized in that the modulation is carried out in phase or frequency by harmonic oscillations.  5. The method according to claim 1, characterized in that as a nonlinear medium without an inversion center, a quadratic nonlinear medium is used.  6. The method according to claim 1 or 5, characterized in that crystalline quartz is used as a non-linear medium without an inversion center.  7. The method according to claim 1, characterized in that as a non-linear medium without an inversion center, a cubic non-linear medium placed in a constant electric field is used.  8. The method according to claim 1 or 7, characterized in that as a nonlinear medium without an inversion center, a cubic nonlinear medium placed in a constant electric field in which one of the natural transition frequencies is equal to or close to or a multiple of the frequency generated in this medium is used oscillations or waves whose energy is accumulated by resonators.  9. The method according to claim 1, characterized in that as a non-linear medium without an inversion center, a non-linear medium without an inversion center is used, which additionally has negative absorption at the frequency of oscillations or waves generated in this medium, the energy of which is accumulated by means of resonators.  10. The method according to claim 1, characterized in that as a nonlinear medium without an inversion center, a nonlinear medium without an inversion center is used, the size of which along the propagation direction of the modulated optical radiation does not exceed the length of the coherent interaction. 11. The method according to claim 1, characterized in that as a non-linear medium without an inversion center, a set of non-centrosymmetric crystals in contact with each other, the size of which along the propagation direction of the modulated optical radiation does not exceed the length of the coherent interaction, is used, while the non-centrosymmetric crystals are oriented relative to each other so that non-linear polarization waves in crystals each time passing through another crystal experience a phase jump of π.
12. The method according to claim 1, characterized in that as a non-linear medium without an inversion center, a non-linear medium without an inversion center with fiber or waveguide geometry is used.  13. The method according to claim 1, characterized in that as the resonators use one resonator of the microwave range, and a nonlinear medium without an inversion center is placed inside it.  14. The method according to claim 1, characterized in that one resonator of the microwave range is used as resonators, and a nonlinear medium without an inversion center is placed outside this resonator, while the converted energy of the oscillations or waves generated in this medium is supplied to the resonator.  15. The method according to claim 1 or 14, characterized in that between the nonlinear medium without an inversion center and a resonator an isolation valve device is arranged.  16. The method according to claim 1, characterized in that one microwave resonator with a capacitive gap is used as the resonator, and a nonlinear medium without an inversion center is placed in this gap.  17. The method according to claim 1, characterized in that the resonator uses an oscillatory circuit, while a nonlinear medium without an inversion center is placed between the capacitor plates of this oscillatory circuit.  18. The method according to claim 1, characterized in that a superconducting resonator is used as a resonator.  19. The method according to claim 1, characterized in that the accumulation of the converted energy is carried out by sequentially arranging along the propagation of the modulated optical radiation several sections of a nonlinear medium without an inversion center with resonators corresponding to these sections, which accumulate the energy converted on each section of the given medium.  20. The method according to claim 1, characterized in that the accumulation is carried out by repeatedly passing the modulated optical radiation in a closed loop through the same section of a nonlinear medium without an inversion center with a corresponding resonator that stores energy converted in this section of the medium.  21. The method according to p. 1, characterized in that the accumulation of the converted energy is carried out using several resonators with the same resonant frequency, while the resonators are combined into cascades through valve elements passing the accumulated converted energy in one direction from the resonator of the previous cascade to the cavity of the subsequent stage, and a nonlinear medium without an inversion center is located both inside the cavity of the first stage and outside it.  22. The method according to claim 1, characterized in that the modulation of optical radiation and energy conversion in the form of the generation of electromagnetic waves or waves is carried out in the same nonlinear medium without an inversion center having electro-optical properties.  23. The method according to claim 1, characterized in that the energy conversion is carried out in the same nonlinear medium without an inversion center, which additionally has electro-optical and piezoelectric properties, while the natural frequency of elastic vibrations of this medium must coincide with the frequency of electromagnetic waves generated in this medium oscillations or waves, and a piezoelectric resonator is used as a resonator, of which this medium is a part.  24. The method according to claim 1, characterized in that the modulation is carried out by high-frequency electromagnetic waves to be amplified, while the resonant frequency of one or more resonators is chosen equal to the modulation frequency.  25. The method according to claim 1 or 24, characterized in that they provide positive feedback using the feedback circuit between the converted oscillations, the energy of which is accumulated in the resonator, and modulating electromagnetic oscillations.  26. The method according to p. 1 or 24, characterized in that the resonant frequency of one or more resonators is selected a multiple of the modulation frequency.  27. The method according to claim 1, characterized in that as the optical radiation using continuous laser radiation.  28. The method according to claim 1, characterized in that the laser radiation of the pulsed action is used as optical radiation, provided that the time duration of the pulse substantially exceeds the period of modulating oscillations.  29. The method according to claim 1, characterized in that the radiation of the Sun is used as optical radiation.  30. The method according to clause 29, characterized in that the energy is converted on a space object with subsequent transfer of the converted energy of microwave electromagnetic waves to the Earth, while the modulation frequency of solar radiation is selected so that the resonant frequency of one or more resonators is within frequency range of atmospheric transparency.  31. The method according to claim 1, characterized in that they use optical systems to focus the optical radiation and give the beam of modulated optical radiation a predetermined shape when it propagates in a nonlinear medium without an inversion center.  32. The method according to claim 1, characterized in that the parallel conversion of energy of several streams of optical radiation is carried out simultaneously, while the converted and accumulated energy from each stream of optical radiation is sent to one common channel for transmitting the resulting converted energy from all streams of optical radiation.

Images