FR3122742A1 - Method and device for analyzing high rate, deep and broadband terahertz modulation - Google Patents

Abstract

Method and device for analyzing terahertz modulation at fast, deep and broadband rate The present invention relates to a device for modulating terahertz waves comprising a primary medium (1), a secondary medium (2), a laser (3), a membrane (4) secured to the primary support (1), a protective casing (5), and an optical mounting bracket (6) secured to the casing (5); said device is remarkable in that it comprises terahertz wave modulation means based on a III-V semiconductor layer whose permittivity is optically modified by a photogeneration process to maximize the modulation efficiency by means modulation of the permittivity. Another object of the invention relates to a wideband terahertz modulation method. Figure 1

Description

Method and device for analyzing high rate, deep and broadband terahertz modulation

The present invention relates to a tunable, deep, versatile and high-speed broadband terahertz modulation analysis method and device, and more particularly, to a terahertz wave modulator capable of performing terahertz wave modulation based on the injection and diffusion transport of electron-hole pairs excited by incident light and to perform various types of modulations based on the intensity of an incident wave and a III-V semiconductor material such as an indium arsenide material.

State of the art

In the field of transmission modulation in commercial terahertz modulators, four different systems are well known: III-V high electron mobility transistors (HEMTs), complementary metal-oxide-semiconductor (CMOS) silicon circuits, microbolometers and pyroelectric devices that operate at room temperature.

All these modulation systems nevertheless have several disadvantages: bulk, low modulation speed, shallow modulation at room temperature and narrow operating range in THz frequencies. This limits them to the rapid emergence of this terahertz spectral range in large-scale industrial applications.

In particular, various methods of using a newly developed terahertz wave in an electromagnetic wave range have been proposed recently.

An example of these methods may include a method of using the designer's surface plasmon resonance generated in a terahertz wave, a method of using a metamaterial, a method of controlling the amplitude of a terahertz wave based on a method of excitation of free electrons in a III-V semiconductor, and others.

Document US2014/001379A1 is known in particular, in which the efficiency of the modulation has been pushed even further by using an organic material.

The mode-locked femtosecond lasers of the 1990s spurred the development of time-domain THz spectroscopy (THz-TDS). This is a first step to demonstrate the possibility of THz detection and imaging for the first time. However, it requires a high pumping power to obtain a significant modulation of the birefringence of the sensor crystal. Despite its performance, it was bulky and expensive.

Another approach to controlling THz wave radiation is metamaterials. Metamaterials are passive components that provide a versatile platform for manipulating the phase, polarization, or intensity of electromagnetic waves.

However, these metamaterials operate in a narrow terahertz frequency. Active components such as hybrid components have been studied but they are limited by spectral and modulation actions since the spectral shift for resonances is accompanied by decreasing efficiency.

Multi-layered metamaterials have been created to modulate a specific frequency, however, this approach is limited in broadband tunability due to the static geometry of the structures.

Multilayer metamaterials with a 1D structured surface have been simulated, based on a principle known for infrared waves, to have a dynamic control of the electrical or magnetic polarization of terahertz waves.

Multilayered metamaterials with a 2D structured surface were also simulated, relying on a principle known for infrared waves, to have a dynamic control of the chirality properties of terahertz waves.

Attempts to modulate terahertz waves directly from the terahertz source to control the amplitude, phase, polarization, etc., of a transmission wavelength in various electromagnetic wavebands, have been widely realized. , but the modulation speed and coherence of the generated terahertz wave is limited when there is a fast modulation rate.

Terahertz synchronous sensing is a widely used technique. However, this remains a significant obstacle for terahertz applications that depend on fast modulation (eg, real-time imaging in a treadmill).

Attempts to improve the signal-to-noise ratio (SNR) in the amplifier chain of a terahertz receiver are very popular to obtain the maximum sensitivity and terahertz information. However, the modulation of terahertz waves is limited to a few hundred kHz. Modulating the terahertz detector sensitivity limits the signal-to-noise ratio (SNR) for current terahertz applications.

To sum up, the main reason why terahertz technology has not yet been implemented in the field of applications is due to the lack of instrumentation to control terahertz electromagnetic waves in a versatile way. Terahertz sources are mature technologies since they reuse technologies available in other frequency ranges; this is why we have a wide range of terahertz source instrumentation. Terahertz detection is also a mature technology, however the sensitivity of the receiver chain of the terahertz detector is still very limited. It is for this reason that there is still a lack of terahertz modulators due to the lack of electro-optical materials sensitive to a terahertz wave to create general-purpose terahertz modulators.

Disclosure of Invention

The present invention aims to provide a terahertz wave modulator with high modulation rate, miniaturized, and capable of modifying a transmitted terahertz wave in a variety of ways and maximizing the efficiency of the modulation coupled with a method controlled by software through firmware and electronic control.

Further, the present invention aims to provide a terahertz wave switching device capable of modulating the transmission of a terahertz wave at room temperature and uniformly modulating the amplitude over a wide band of the terahertz range.

In addition, the passive device (optical blade) is now fully active having the characteristic of dynamically reflecting and absorbing the terahertz wave.

The present invention integrates a unique terahertz simulation tool which helps the user to better understand the physical phenomenon involved and to calculate the best combination of parameters for a given application.

The present invention integrates software and firmware that allows full control of the device while obtaining real-time information.

To this end, and in accordance with the invention, a terahertz wave modulation device is proposed comprising a primary support, a secondary support, a laser, a membrane integral with the primary support, a protective casing, and a optical assembly secured to the housing; remarkable in that it comprises terahertz wave modulation means based on a layer of III-V semiconductor whose permittivity is optically modified by a photogeneration process to maximize the modulation efficiency by means of modulation of permittivity.

Such a high rate terahertz wave modulation device provides a great contribution for terahertz spectroscopy instrumentation for applications such as gas detection, telecommunications, imaging, non-destructive testing, bass sources and high power for spectroscopy systems and astronomical instrumentation.

The terahertz wave modulation device according to the invention also offers a miniaturized industrial solution, which thus allows the adoption of this product in applications in a large number of fields.

Indeed, current gas detectors use infrared technology but are unable to detect natural gases at high resolution.

Terahertz waves are widely used for non-destructive inspection applications of composite materials thanks to the terahertz electromagnetic properties that allow them to pass through non-metallic polymer materials.

A device for modulating terahertz waves at a high modulation rate for low and high power sources of the electro-vacuum type (“electro-vacuum” in English) makes it possible to obtain a higher switching rate. Resistance to terahertz flux for high power sources, for example 1 W, is an advantage of the device according to the invention since the diameter of the beam in the terahertz modulation device will not be less than 1 mm ² . This therefore results in low power densities far removed from damage thresholds opening up to fields such as that of cyclotrons, and also to the field of telecommunications.

A high modulation rate terahertz wave modulation device in astronomical instrumentation offers faster room for maneuver in calibrations than for front-end type applications.

For these latter applications based on terahertz spectroscopy, rapid modulation on the part of the terahertz modulator according to the invention makes it possible to increase the signal/noise ratio of the terahertz spectroscopy analysis thanks to the high modulation rate for this type of apps.

Preferably, the means for modulating the permittivity consist of the laser. As a variant, other types of stimuli than the laser are possible, such as for example thermal, mechanical and electrical.

Furthermore, the device may comprise means for modulating the width of the wavelength, the amplitude and/or the phase, by the deformation of the waveform in the time domain, coupled with a structuring of the surface to induce phenomena like a designer's surface plasmon.

The device may also include a vertically incident focused terahertz wave radiation unit radiating a wave incident on the III-V semiconductor layer.

The device can also comprise a microcontroller connected to the terahertz wave modulation means, the microcontroller storing firmware capable of generating high-resolution signals for controlling the terahertz wave modulation means.

Another object of the invention relates to a method for modulating terahertz waves, the method being implemented by a device comprising a primary support, a secondary support, a laser, a membrane secured to the primary support, a protective casing, and an optical mounting bracket secured to the housing; remarkable in that the device comprises terahertz wave modulation means based on a III-V semiconductor layer, and in that the method comprises a step of optical modification of the permittivity of a semiconductor layer III-V by a photogeneration process to maximize modulation efficiency by permittivity modulation means.

Said method may also comprise a step of modulating the width of the wavelength, the amplitude and/or the phase, by the deformation of the waveform in the time domain, coupled with a surface plasmon of a designer or with a metamaterial.

Said method can also comprise a step of calculating the permittivity by solving a transport equation of the photogenerated charges coupled and controlled by the ambipolar diffusion coefficient for the free carriers.

Advantageously, the device further comprises a microcontroller connected to the terahertz wave modulation means, the microcontroller storing firmware capable of generating high-resolution signals for controlling the terahertz wave modulation means. Said method can then also comprise a phase, implemented by the firmware, of controlling the terahertz wave modulation means, said phase comprising a first step of receiving a control signal transmitted via a wireless communication link, said control signal corresponding to a predetermined terahertz center frequency, a second step of generating a high resolution signal, and a third step of transmitting the high resolution signal to the terahertz wave modulation means for controlling these means at said predetermined terahertz center frequency.

Advantageously, a correspondence table storing pairs of terahertz central frequencies/laser diode pump irradiance values is initially transmitted to or pre-implemented in the firmware, each laser diode pump irradiance value being chosen such that this value maximizes the transmission of the terahertz wave for the central terahertz frequency with which it is associated, and, during the control phase of the terahertz wave modulation means, the high-resolution signal generated and transmitted by the firmware allows, via the correspondence table, to apply the best pump irradiance to the laser, for said predetermined terahertz center frequency.

This attractive technique, together with a method based on line-by-line analysis, results in a versatile, depth-modulated, fully reconfigurable, high-speed device operating over a wide range of frequencies in the terahertz range. In order to control the device, firmware and software are required. The firmware generates high resolution signals and controls the modulation with high precision. The software provides a method for evaluating the quality of the measurement of the modulation of terahertz waves through a user-friendly interface allowing the whole system to be controlled. The software will also contain a simulation section where the user can perform theoretical simulations and better understand the terahertz phenomenon.

The present invention also finds application in the creation of a new generation of terahertz telescopes. Instead of using only an optical actuator (laser) for the telescope which irradiates a III-V semiconductor membrane, it is possible to use an array of optical actuators, each optical actuator comprising a wave modulation device terahertz as described above. This network of actuators makes it possible to reproduce a Shack-Hartmann wavefront sensor by modifying the refractive index of a large membrane in III-V semiconductor material using different laser irradiances. The change in refractive index can be used to control the intensity, phase, and polarization of terahertz waves. The terahertz wave can also be modulated with broadband tunability, deep and high-speed modulation. This technology reduces the influence of mechanical vibrations and electronic noise that occur with the current state of the art in the field of telescope instrumentation. The high-speed modulation rate provides a high signal-to-noise ratio (SNR). Such astronomical instrumentation equipment is intended for astrophysics applications that have an immediate need to find suitable technology to create a terahertz telescope.

Other advantages and characteristics will emerge better from the following description of a single alternative embodiment, given by way of non-limiting example, of the method and of the device for analyzing broadband terahertz modulation and at rapid and deep modulation, in accordance with the invention and with reference to the list of the following drawings, in which:

, the is an exploded perspective view of the device according to the invention, the device comprising a primary support, a secondary support, and a casing consisting of two shells;

, the is an assembled perspective view of the device of the ;

, the is a side view of the device from the ;

, the is an assembled perspective view of the device of the , during its operation, and in which the two housing shells have been omitted;

, the is an enlarged view, in perspective, of the primary and secondary supports of the device of the , during operation; and

, the is a longitudinal sectional view of the primary support of the , illustrating incident and reflected terahertz waves.

Mode of carrying out the invention

According to one aspect of the present invention, there is provided a terahertz wave modulator, comprising: (a) (i) a III-V semiconductor substrate which is the terahertz modulation layer 4; and (b) a first vertically incident focused terahertz wave radiation unit radiating a first incident wave 10 (the first radiation unit not being shown in the figures, the incident wave 10 being visible in Figures 2 to 6) comprising a terahertz wave region to be incident vertically on the terahertz modulation layer 4. The incident wave 10 is focused in order to be able to pass through holes in the layer 4 which have a diameter of the order 2.25mm.

The layer of III-V semiconductor material 4 can be undoped or doped, such as an indium arsenide membrane acquired commercially or by epitaxial growth.

The layer of III-V semiconductor material 4 can be deposited on a support 1 by an epoxy glue. The appropriate thickness of the layer of III-V semiconductor material 4 can be obtained by dry or wet chemical etching methods to smooth the surface.

The terahertz wave modulator may further comprise: (c) a second incident wave radiation unit 3 12 which radiates the terahertz wave region, at a controlled angle (optimized at the Brewster angle which is 74 degrees in the indium arsenide material) to be incident on the terahertz modulation layer 4. The second unit 3 of incident wave radiation 12 homogeneously illuminates the layer of III-V semiconductor material 4. As illustrated in FIGS. 3 to 6, the incident wave 12 which strikes the layer of III-V semiconductor material 4 produces a reflected wave 14.

The second incident wave 12 (visible in FIGS. 2 to 6) is a collimated wave in the near infrared (for example at 808 nm at 500 mW) which can be a continuous or pulsed wave which comes for example from a laser diode of of the PIN diode type, or even a surface-emitting vertical-cavity laser diode, or VCSEL (from the English “Vertical-Cavity Surface-Emitting Laser”). In the latter case, the laser diode is in fact more compact and allows modulation of the terahertz waves at high rate with a high signal-to-noise ratio for the terahertz wave.

The terahertz wave region on the terahertz modulation layer 4 should be homogeneously irradiated by the radiation of the second incident wave 12 having a predetermined spot diameter pattern, larger than the diameter of the support 1 and than that of the layer 4. The second incident wave 12 penetrates the III-V semiconductor membrane 4 such as indium arsenide located on the holding support 1, and thus produces, by photogeneration, electron-hole pairs inside of the III-V semiconductor membrane 4. The carrier density shifts the plasma frequency of the material beyond the terahertz range. This means that the focused terahertz beam 10 "sees" the III-V semiconductor membrane 4 with a different refractive index when the second incident wave 12 illuminates the membrane 4.

Thus, with reference to Figures 1 to 4, the device comprises a primary support 1, a secondary support 2, a laser 3, a membrane 4 secured to the primary support 1, a protective casing 5, and an optical assembly support 6 secured to the housing 5. The device may also comprise a slotted base optical support 9, configured to receive the optical mounting support 6. The primary support 1 is typically inserted into the secondary support 2. As illustrated in Figures 1 and 2, the protective casing 5 typically consists of two complementary shells. Optical mounting bracket 6 is typically secured to housing 5 by a hex nut 7.

According to another aspect of the present invention, there is provided a terahertz wave switching device, comprising: the terahertz modulator and further comprising a second incident wave radiation control unit (such a unit not being shown in the figures) determining whether the second incident wave is radiated.

The simulator present in the software contains business logic directly derived from theoretical work and translated into a programming language. This programming language must be optimized for heavy calculations as well as for image processing.

A communication protocol has been established between software and hardware using serial communication which is an industry standard. All communications between software and firmware are subject to controls, with software and firmware to be maintained over time through patches and/or updates.

Any user interface framework or programming language can achieve the same user interface experience but said language must support communication protocols and also draw graphics and generate images.

As mentioned above, according to the embodiments of the present invention, the terahertz wave modulator based on a III-V semiconductor layer whose permittivity is optically changed by a photogeneration process can maximize the modulation efficiency by using the modulation of permittivity which is calculated by solving an equation called the ambipolar rate equation for free carriers. The means for modulating the permittivity are typically made up of the second radiation unit 3. The resolution of such an equation of the ambipolar rate can for example be carried out via numerical calculations. Such calculations thus make it possible to calculate the modulation of the permittivity induced by the injection of photogenerated carriers on the indium arsenide membrane 4.

More specifically, within an undoped (or slightly n-doped) indium arsenide membrane, an infrared pump generates electron-hole pairs whose density N is governed by the charge transport equation and which is controlled by the ambipolar diffusion coefficient for the InAs material with the diffusion length parameters and the lifetime of its photocarriers. This equation is described by the following equation (1):

(1);

where G ^op represents the optical generation and τ _r the recombination lifetime of the photocarriers, and where an intrinsic indium arsenide membrane is considered (n _i = n ₀ = p ₀ ), and where the mobility µ _a and the ambipolar diffusion coefficient D _a are given by the following relations (2) and (3):

(2);

where D _(n,p) represent, respectively, the diffusion coefficients of electrons and holes related by Einstein's relation. The ambipolar diffusion coefficient in an undoped indium arsenide membrane is D _a = 23.5 cm ² s ^-1 at a temperature of 300 K.

Note that the ambipolar rate equation (1) is governed by the minority carriers. This is due to the fact that the photocarriers created by the photogeneration process diffuse together ∆n(x,t) ≈ ∆p(x,t) which corresponds to ambipolar diffusion. In this context, photocarriers with a low mobility value (normally minority carriers, more precisely holes) cause a deceleration of ambipolar diffusion. The majority carrier density is not affected by irradiation, except under very strong excitation conditions.

The intensity of the incident wave is supplied to the device to modulate the amplitude of the THz wave, and can be implemented as the highly functional terahertz wave modulation device by being coupled with a surface plasmon of a designer or with a metamaterial to decrease the intensity of the wave which makes it possible to change the refractive index of the THz modulator and be widely used for optical purposes.

Thus, the present invention allows efficient and dynamic control of incident THz waves over a wide range of frequencies in the terahertz range with very low pump intensity incident light.

By mixing in a single system the theory of fundamental physics (for example, the Maxwell and transfer equations) with the data of the embedded system in real time, the device according to the invention provides the user with a unique tool for calculating optimal system settings. This opens the door to machine learning functions in the future.

Simulate the structure of a terahertz modulator driven by photo-generation.

The input parameters provided by the user are typically:

• Center frequency Terahertz
  • continuous terahertz wave
  • Pulsed terahertz wave
  • A data range with extrema as well as the step
• The type of modulation applied to the laser which comes for example from a laser diode:
  • Continuous: no modulation
  • Continuous modulated: a modulation frequency entered by the user Pulsed wave: no modulation
  • Modulated pulse wave: a modulation frequency entered by the user
• Architecture of the III-V semiconductor material
  • each material combination is selectable as a “modulator class”

- The development of R&D:

The method is carried out by numerical calculations in the C++ language as described below.

In the software code, one can consider a structured multilayer membrane, or a multilayer membrane, or simply a simple membrane standing in air at room temperature. The membrane is irradiated by a plane wave which comes for example from a laser diode at 74° which corresponds to the Brewster angle of the InAs material at an infrared wavelength of 808 nm or close, this corresponds to the emission of 'a commercial laser where the reflection of the infrared laser is reduced to a minimum. The permittivity of the III-V semiconductor-based membrane is described by a Lorentz-Drude model where the III-V material parameters are related to the infrared frequency. The normalized total electric field is calculated by the diffusion matrix method. The IR pump generates photogenerated carriers inside the III-V semiconductor membrane whose density of photogenerated carriers is driven by the ambipolar transport equation. The photogenerated carriers will diffuse inside the membrane at a distance linked to the ambipolar diffusion length. The ambipolar diffusion length on the membrane depends on the effective recombination lifetime of the photogenerated carriers which takes into account Auger recombination, radiative recombination and the Shockey-Read Hall recombination process.

The ambipolar equation is highly nonlinear due to the dependence of the ambipolar scattering length on the density of photogenerated carriers.

To solve this equation, we use the principles of the theory of fundamental physics with, among others, the Maxwell and charge transport equations. The permittivity of the membrane can then be calculated from its characteristics (class of membrane), the way in which it is irradiated (irradiance value of the pump) and the central frequency to be modulated.

Once the permittivity has been calculated, it is possible to calculate the transmission, reflection and absorption of a terahertz wave crossing the membrane.

The input parameters provided by the software are typically:

• the central frequency to be modulated
• a pump value that comes for example from a laser diode
• a modulation class

The output results delivered to the software internally are typically:

• a transmission coefficient
• an absorption coefficient
• a reflection coefficient
• the permittivity of the membrane

The resolution of this equation is used by an algorithm which makes it possible to calculate the various coefficients for various values of central frequency and pump irradiance. In this algorithm, the different transmission coefficients are calculated for a range of frequencies and for a range of pump values. A 2D transmission matrix is thus obtained. In the same way, the other output results can be calculated internally.

The input parameters provided by the user are typically:

• either a specific frequency or a range of frequencies
• a range of specific pump values if the default values are not suitable
• a modulation class to use

The output results delivered to the user are typically:

• several types of graphs available but not all of them are displayed so as not to overload the interface. One can, for example, generate a “heatmap” type graph of the transmission with a range of terahertz electromagnetic waves for the abscissa and a range of laser intensity for the ordinate.

It should be noted that the user can change the type of view and that the results stored in memory prevent unnecessary and repetitive calculations.

This Multiphysics section of the software could adopt new features and analyzes such as plasmonic effects, irradiation of new infrared sources at terahertz waves among many others in the terahertz and photonics industry.

This software can be coupled with an embedded system section in order to introduce the commands in a compact and ergonomic hardware.

From the resolution of the ambipolar equation, it is also possible to create an algorithm responsible for creating the look-up table of the software or LUT (for “Look-Up Table” in English). We first calculate the 2D transmission matrix by reusing the previously described algorithm. Once obtained, one calculates, for each central frequency, which pump value maximizes the transmission of the terahertz wave. This frequency-pump couple (which comes for example from a laser diode) is calculated for each frequency and saved in the correspondence table. Once this correspondence table has been calculated, it is transmitted to the firmware so that it can apply the best pump irradiance for a given frequency.

This section of the embedded system is responsible for the intelligence of the product by sending commands through serial communication from the software to the hardware. This section synchronizes multiphysics, electronics and optics in order to obtain an innovative industrial solution to dynamically control high-speed terahertz waves, with broadband tunability and deep modulation. The synchronization and also the interpretation of the commands is the fundamental core of the invention.

- The input parameters are:

• control of the laser which comes for example from a laser diode
  • On/Off
  • Modulation frequency
• Diaphragm type
  • the type of "modulator class"
• Central terahertz frequency
  • specify the frequency to be modulated

- R&D development:

The embedded system is produced in C++ language and the main commands to be executed by the hardware are described below:

The embedded system sends commands via serial communication to the hardware which interprets the commands. Basically the commands are different laser mode operations such as:

Mode 1:

▪ Adjustment of the intensity variation of the IR laser from 0 to 10W/cm^2

Mode 2:

▪ Adjustment of the TTL modulation frequency up to frequency values of the order of terahertz

Mode 3:

▪ Adjustment of the pulse width of the laser which comes for example from a laser diode

Mode 4:

▪ Adjustment of the laser delay which comes for example from a laser diode

- Output results delivered to the user:

The user gets an acknowledgment for each command sent such as an area with the history of commands, responses and diagnostic messages. An error message is displayed if there is a failure when sending commands. An error message is also displayed if the firmware encounters an unexpected error.

The embedded platform works using the same input parameters added in the software section. The synchronization of the Multiphysics and Embedded System sections of the software gives the user complete control by testing in real time in hardware which makes terahertz waves and technology very user-friendly. For example, this invention makes possible the modeling of III-V membranes, numerical simulation and calculation to improve the knowledge of terahertz waves and the comparison between numerical calculation and real-time experimental data of terahertz electromagnetic waves.

Thus, this invention based on new software and hardware provides a solution for terahertz sources and detection systems:

- Terahertz detectors:

Improves the signal-to-noise ratio of synchronous heterodyne detection.

- Terahertz sources:

Modulate terahertz waves without impacting the generator.

The unique software and hardware technology is ready for custom terahertz frequency modulation. Providing high-speed modulation in the MHz range and terahertz broadband tunability down to 2THz, both with depth modulation.

The system proposed in this invention is able to unify Multiphysics, Embedded System and Hardware for a revolutionary product that is compact, ergonomic and high performance to handle any type of terahertz radiation. Today the study of terahertz waves remains marginal and underdeveloped and requires knowledge both in programming but also in the field of terahertz. The system will be able to extend terahertz technology to a wider audience by modeling complex results into accessible and understandable graphs.

It is observed that today there are multiphysics software on the market such as COMSOL or CST studio. However, they lack the two features to simulate and control the embedded system to send commands from the software to the hardware tool to control a terahertz modulator.

Finally, it is quite obvious that the examples which have just been given are only particular illustrations in no way limiting as to the fields of application of the invention.

Claims (11)

Device for modulating terahertz waves comprising a primary support (1), a secondary support (2), a laser (3), a membrane (4) secured to the primary support (1), a protective casing (5), and an optical mounting support (6) secured to the casing (5), characterized in that it comprises means for modulating terahertz waves based on a layer of III-V semiconductor (4) whose permittivity is optically modified by a process of photogeneration to maximize the efficiency of modulation by means of modulating the permittivity. Device according to Claim 1, characterized in that it comprises means for modulating the width of the wavelength, the amplitude and/or the phase, by the deformation of the waveform in the time domain, coupled with a surface plasmon from a designer or with a metamaterial. Device according to Claim 1 or 2, characterized in that it further comprises a vertically incident terahertz wave radiation unit radiating an incident wave (10) on the III-V semiconductor layer (4). Device according to any one of the preceding claims, characterized in that the means for modulating the permittivity consist of the laser. Device according to any one of the preceding claims, characterized in that it further comprises a microcontroller connected to the terahertz wave modulation means, the microcontroller storing firmware capable of generating high-resolution signals for controlling the modulation of terahertz waves. A terahertz telescope comprising an array of optical actuators, each optical actuator comprising a terahertz wave modulation device according to any preceding claim. Method of modulating terahertz waves, the method being implemented by a device comprising a primary support (1), a secondary support (2), a laser (3), a membrane (4) integral with the primary support (1) , a protective casing (5), and an optical assembly support (6) secured to the casing (5), characterized in that the device comprises terahertz wave modulation means based on a layer of III- V (4), and in that the method comprises a step of optically modifying the permittivity of the III-V semiconductor layer (4) by a photogeneration process to maximize the modulation efficiency by modulating means permittivity. Method according to Claim 7, characterized in that it comprises a step of modulating the width of the wavelength, the amplitude and/or the phase, by the deformation of the waveform in the time domain, coupled with a surface plasmon from a designer or with a metamaterial. Method according to Claim 7 or 8, characterized in that it comprises a step of calculating the permittivity by solving an equation of the ambipolar rate for the free carriers. Method according to any one of Claims 7 to 9, characterized in that the device further comprises a microcontroller connected to the terahertz wave modulation means, the microcontroller storing firmware capable of generating high resolution signals, and in that that the method further comprises a phase, implemented by the firmware, of controlling the terahertz wave modulation means, said phase comprising a first step of receiving a control signal transmitted via a wireless communication link, said control signal corresponding to a predetermined terahertz center frequency, a second step of generating a high resolution signal, and a third step of transmitting the high resolution signal to the terahertz wave modulation means for controlling these means at said predetermined terahertz center frequency. Method according to Claim 10, characterized in that a correspondence table storing pairs of terahertz center frequencies/laser diode pump irradiance values is initially transmitted to or pre-established in the firmware, each laser diode pump irradiance value being chosen such that this value maximizes the transmission of the terahertz wave for the central terahertz frequency with which it is associated, and in that, during the control phase of the terahertz wave modulation means, the signal at high resolution generated and transmitted by the firmware makes it possible, via the correspondence table, to apply the best pump irradiance to the laser (3), for said predetermined terahertz central frequency.