20 results about "Terahertz quantum cascade laser" patented technology

The invention discloses a monometallic waveguide GaN-based terahertz quantum cascade laser, which is characterized in that the bottommost layer of the structure is a substrate, an n-type highly-doped n + + layer, a QCL active region and an n-type doped layer are sequentially arranged on the substrate, a cathode electrode layer is arranged on the n-type highly-doped n + + layer, an anode electrode layer is arranged on the n-type doped layer, and an anode electrode layer is arranged on the anode electrode layer. Wherein the substrate is a GaN substrate, an AlN substrate or a SiC substrate. The invention also discloses a preparation method. On the basis of systematic research on refractive index related parameters of GaN under THz frequency, absorption of single-metal waveguide structure parameters on QCL light field limiting factors and free carriers is analyzed, and QCL with high light field limiting factors and low loss of different substrates is designed. Besides, according to the designed active region structure, the gain can reach 88 / cm at 10K and can reach 34 / cm at 280K, the corresponding wavelength is 6.6 THz, and the frequency which cannot be achieved by a traditional GaAs system is achieved.

The invention relates to a terahertz near-field imaging light path calibration device and a terahertz near-field imaging light path calibration method. The device comprises a first visible light source, a second visible light source, a first collimation visible light source, a second collimation visible light source, a first light path collimation system, a second light path collimation system, a light path adjusting system, a circular reflector, a terahertz quantum cascade laser, a thermal detection array, a terahertz quantum well detector and an atomic force microscope platform. The THz laser source and the detector are simulated through the divergent visible light source, the lifting position point of the light path is calculated, light beams can be accurately coupled to the position of the needle point after being focused, errors caused by improper light path adjustment are reduced, meanwhile, the overlapping effect of light spots at the needle point is calibrated through the circular reflector and the thermal detection array, and the detection accuracy is improved. And the thermal detection array is used for observing the convergence effect of THz reflection light spots at the position of the detector, so that the effective focusing and coupling efficiency of THz waves in a near-field region of a probe sample can be improved.

The invention discloses a compact integrated gas monitoring system based on terahertz waves, which relates to the technical field of gas detection and comprises a terahertz quantum cascade laser, an information acquisition device, a first parabolic mirror, a gas chamber, a second parabolic mirror, a reflection device, a communication module, a terahertz wave frequency adjusting device and a shell. According to the system, the terahertz wave technology is utilized, and the laser wavelength corresponding to the specific gas absorption spectrum is selected, so that high-selectivity detection of target gas is realized, and interference of other gases is avoided; according to the system, a self-mixing interference technology is adopted, a laser serves as a receiver, gas is detected by monitoring voltage changes at the two ends of a QCL terminal, and the system has high safety, rich spectral information, high sensitivity to low-concentration gas, strong anti-interference capability and real-time monitoring capability; reflection and transmission of terahertz waves are adjusted through temperature control, accurate recognition of gas types and components is achieved, and an effective means is provided for environment monitoring and safety early warning.

This invention relates to a dual-comb control system for a terahertz quantum cascade laser, comprising a first terahertz quantum cascade laser, a second terahertz quantum cascade laser, a first T-type biaser, and a second T-type biaser. The first terahertz quantum cascade laser operates in optical frequency comb mode, while the second terahertz quantum cascade laser operates above a threshold current. The first and second terahertz quantum cascade lasers emit terahertz light from each other. The first terahertz quantum cascade laser also functions as a detector to detect a mixing signal. The state of the mixing signal is switched by changing the power of the radio frequency signal generated by the radio frequency source. This invention enables the switching of the mixing signal between chaotic, unstable, and dual-comb states under high drive current, significantly improving the spectral width and application scenarios of the dual-comb system based on the quantum cascade laser.

The invention discloses a high-integration and multi-reflection gas content detection device based on terahertz waves, and relates to the technical field of gas detection, and the high-integration and multi-reflection gas content detection device comprises a terahertz quantum cascade laser, an information acquisition device, a first parabolic mirror, a gas chamber, a second parabolic mirror, a spherical reflection cavity and a reflector. According to the invention, the structure of the laser detector is optimized, the terahertz quantum cascade laser self-mixing technology is utilized to realize accurate detection, the multi-reflection technology is adopted to increase the optical path so as to improve the measurement accuracy, and a high-sensitivity, rapid, continuous and safe detection means is provided.

The present application relates to a kind of wide spectrum terahertz quantum cascade laser heteroactive region, the heteroactive region is arranged between the lower electrode contact layer and the upper electrode contact layer of terahertz quantum cascade laser epitaxial structure;The heteroactive region is sequentially stacked by four kinds of sub-active regions with different center emission frequencies along the epitaxial growth direction;The four kinds of sub-active regions all adopt GaAs / AlGaAs two-trap fast phonon single period structure, and different center emission frequencies are formed by adjusting the thickness of two GaAs quantum well layers in each sub-active region.The present application uses four kinds of sub-active regions with different center emission frequencies to form heteroactive region, and utilizes the characteristics of the small thickness of two-trap active region single period, integrates more cascade cycles under the condition of limited total active region thickness, so as to obtain the total gain spectrum output wider than single active region.

In order to provide a THz-QCL element which takes advantage of the characteristics of a ZnO-based semiconductor material, a quantum cascade laser element has a semiconductor superlattice structure (a QCL structure), wherein the semiconductor superlattice structure has a plurality of unit structures that are stacked repeatedly. Each unit structures comprises three well layers having a composition of ZnO or ZnMgO, and barrier layers having a composition of ZnMgO or MgO that separates each well layer from each other and have a higher ratio of MgO than the left and right wells.

The present application relates to a kind of self-injection terahertz light frequency comb system, wherein, terahertz quantum cascade laser is as light frequency comb source, beat frequency signal generated by self beat frequency is transmitted into first T-type biasing device;First T-type biasing device is used to transmit beat frequency signal to wave divider;Wave divider is used to divide beat frequency signal into two ways, one way is transmitted to circulator and participates in self injection, another way is connected to spectrum analyzer and carries out real-time detection;Circulator is used to keep the one-way transmission of beat frequency signal participating in self injection in loop;Phase shifter is used to phase match beat frequency signal participating in self injection;Second T-type biasing device is used to inject phase-matched beat frequency signal into terahertz quantum cascade laser;Spectrum analyzer is used to detect the self-injection beat frequency signal obtained in real time.The present application can improve the stability of system, meet the requirement as high-frequency optoelectronic oscillator.

The invention discloses a preparation method of a bimetallic waveguide device for a GaN terahertz quantum cascade laser, and the method comprises the steps: providing an epitaxial wafer of a silicon substrate GaN-based terahertz quantum cascade laser, and carrying out the etching of the epitaxial wafer till a silicon substrate, and forming a bar structure; forming a first ohmic contact layer on the surface of the bar; evaporating bonding metal on the surface of the receiving substrate; bonding the epitaxial wafer with the substrate; removing the silicon substrate by adopting a wet etching mode; removing the buffer layer through an inductive coupling plasma etching mode, exposing the bottom n-GaN layer, and forming a second ohmic contact layer; and cleavage is carried out on the bar to obtain the bimetallic waveguide device. According to the method, the tensile strain of the Si-based epitaxial layer is released in advance by etching the epitaxial layer to the growth substrate before wafer bonding, so that the purpose of releasing the stress is achieved, cracks of the epitaxial layer caused by release of the tensile stress after the substrate is removed are avoided, and improvement of the device manufacturing yield is facilitated.

The present invention concerns an up-converted far-infrared photonic source device, comprising the following successive layers: - a ground material (110); - a hetero-structure of semiconductor material having a top surface (120); - a lithographic Bragg grating (125) on the top surface of the hetero-structure, the lithographic Bragg grating having a series of parallel slits with a pitch in the range of 15 to 30 μm; - an electrically powered n-doped conductive (130) with a gold top frame (131) injection contact on the top surface of the hetero-structure; - a dielectric layer (140) deposited on the lithographic Bragg grating; - a plasmonic grating (150,160) realized by a first electrically powered metallic layer (150) with a first series of slits matching the parallel slits of the Bragg grating and a series of second slits between each pair of slits of the first series of slits with a pitch in the range of 3-8 μm, and a second layer of a bi-dimensional conductive material (160) in contact with the first electrically powered metallic layer (150). The invention further concerns a manufacturing method for the up-converted far-infrared photonic source device.

The invention relates to a terahertz grating characterization system based on a self-mixing technology, and the system comprises a terahertz quantum cascade laser which is disposed in a constant-temperature environment and is used for generating multi-mode laser; the optical collimation system is used for collimating the multi-mode laser and forming parallel light beams; the displacement platform is arranged on an irradiation light path of the parallel light beams; the rotating platform is arranged on the displacement platform, is used for mounting a blazed grating to be measured, and can change the incident angle of the parallel light beams by adjusting the angle; the control system is used for controlling the displacement platform, so that the parallel light beams can irradiate the blazed grating to be detected on the rotating platform; and the oscilloscope system is used for observing a signal which is reflected by the blazed grating to be measured and returns to the laser cavity of the terahertz quantum cascade laser, and the signal is acquired by a data acquisition card. According to the invention, the key structure parameters of the blazed grating can be rapidly and accurately measured.

The invention relates to a terahertz multimode laser mode resolution measurement system, and the system comprises a terahertz quantum cascade laser which is used for generating multimode laser; the guiding module is used for guiding the multi-mode laser into the reflecting module; the reflection module adopts a reflection type blazed grating and is used for reflecting a preset laser mode in the multimode laser back into the terahertz quantum cascade laser according to an original light path; and the control acquisition module is used for acquiring the terminal voltage of the terahertz quantum cascade laser and controlling the current source of the terahertz quantum cascade laser based on the terminal voltage. According to the invention, rapid detection of the intensity of the single laser mode under the multi-mode condition is realized.

The invention discloses a bimetallic waveguide structure for a GaN-based terahertz quantum cascade laser, and the structure comprises a metal In layer, a eutectic alloy AuIn layer and a lower electrode metal layer which are sequentially arranged upwards from a receiving substrate, and a ridge-shaped waveguide structure is arranged on the lower electrode metal layer. Each ridge-shaped waveguide structure sequentially comprises a lower n-type heavily-doped contact layer, a GaN / AlGaN multi-quantum well layer, an upper n-type heavily-doped contact layer and an upper electrode metal layer. The invention also discloses a preparation method. The bimetal waveguide structure in the invention has low loss, high optical field limiting factor, low power loss and better heat dissipation performance, and is beneficial to reducing the threshold gain of the laser and increasing the radiation efficiency.

The invention relates to a terahertz scanning tunneling microscope (STM) and a light path calibration method thereof, and the STM comprises a terahertz quantum cascade laser module, a collimation visible light source, a light path adjustment system, a COP lens, a thermal detection array, and a TPX lens, a probe frame and a sample groove which are located in a vacuum cavity. The COP lens and the thermal detection array are used for calibrating the relative position of the terahertz light beam and the green light beam, the collimated green light beam serves as guiding light, coaxial transmission of the two light beams is achieved, the TPX lens transmits and focuses the terahertz light beam and the collimated visible light beam at the same time, the visible light focus point serves as the indication position of the terahertz light focus point, and the detection accuracy is improved. The terahertz pulse can be better adjusted to be coupled to the STM needle point, and the effective focusing and coupling efficiency of the terahertz pulse in the STM tunnel junction can be improved.

This invention relates to a method for etching a ridge waveguide of a terahertz quantum cascade laser. The method includes: (1) providing a terahertz quantum cascade laser material; (2) etching a groove (7) with the same depth and thickness as the lower contact layer on the surface of the material; (3) further etching the material using a dry etching system equipped with a laser interferometer to etch a ridge structure (8), with the groove (7) being etched simultaneously, and the laser interferometer performing online detection on the bottom of the groove; (4) when the intensity of the oscillation signal of the laser interferometer changes abruptly, the bottom of the groove (7) is just etched to the interface between the lower contact layer (4) and the etching stop layer (3), while at this time, both sides of the ridge structure (8) are just etched to the interface between the multi-quantum well active region (5) and the lower contact layer (4). This method can effectively determine the optimal etching depth by adding only a simple groove pre-etching process, thus improving the accuracy of the etching depth of the laser ridge waveguide.

The invention relates to an on-chip terahertz double-optical-comb device and a manufacturing method thereof, that is, two terahertz quantum cascade lasers with the same size and opposite end faces are manufactured on the same substrate, the two lasers can both work in an optical frequency comb mode, the optical frequency comb repetition frequency difference is small, and the optical frequency comb repetition frequency difference is small. Terahertz lasers output by the end face of the laser are coupled and interacted, and a terahertz double-optical-comb spectrum can be generated. The end faces of the lasers are formed through the self-alignment deep etching technology, the edges of the upper electrode metal strips are aligned with the end faces of the lasers, the size consistency of the two lasers is good, the end face direction is not restrained by the crystal orientation, and on-chip terahertz double optical combs opposite to each other at any angle can be achieved. And a deep etching gap between the two lasers is convenient for placing a sample to carry out terahertz double-optical-comb spectrum detection. The on-chip terahertz double-optical-comb device has the advantages of being compact in structure and high in stability, and has good application prospects.

The application relates to a terahertz quantum cascade laser-based optical communication system, comprising: a transmitting module for generating terahertz waves carrying a modulation signal based on a single-mode terahertz quantum cascade laser; a receiving module for receiving the terahertz waves based on an optical frequency comb terahertz quantum cascade laser and converting the terahertz waves into a radio frequency signal through internal multi-heterodyne frequency mixing; a PLL (Phase-Locked Loop) circuit for generating an error signal based on the radio frequency signal to stabilize the relative frequency drift of the optical communication system; and a signal processing demodulation module for real-time collection of time-domain waveforms and frequency-domain data decoding of the radio frequency signal. The application can realize wideband and high-sensitivity terahertz coherent communication and complete efficient transmission and demodulation of a radio frequency microwave signal.

The application discloses an active region structure of a non-polar plane GaN-based terahertz quantum cascade laser, characterized in that the active region has multiple periods of three-well structure, wherein the potential well layer is GaN and the potential barrier layer is AlGaN; and a corresponding non-polar plane GaN-based terahertz quantum cascade laser. An active region structure of a two-well structure and a laser are also disclosed. The application discloses two active region structures of a three-well resonant phonon and a two-well phonon scattering injection terahertz quantum cascade laser based on a non-polar plane GaN, when the doping is 6*10 10 cm ‑2 , the peak gain of the two structures at 10K is 90.1 and 91.3 cm ‑1 , respectively, at 300K, the peak gain of 41.8 and 44.2 cm ‑ 1 is obtained at 8.2 and 7.7 terahertz, which is higher than the calculated double-metal waveguide loss. The overall results show that at room temperature, a GaN-based terahertz quantum cascade laser is possible at about 8 terahertz.

The present invention discloses a period-broken grating surface-emitting terahertz quantum cascade laser and an optimization method. The present invention introduces a period-breaking structure in the electrode layer, and its potential periodicity ensures the formation of distributed feedback, which can realize the resonance and frequency selection inside the laser. At the same time, due to the non-periodic characteristics of the period-breaking structure locally, its resonant mode is between the symmetric mode and the antisymmetric mode, rather than the antisymmetric mode with low radiation efficiency, so it can effectively improve the radiation efficiency and power of the laser. At the same time, the present invention optimizes the grating parameters through a genetic algorithm, reducing the difficulty and time cost of forward design of the grating structure by analyzing the mode field, and has a high degree of design freedom and flexibility. The terahertz quantum cascade laser grating structure designed by the present invention has high radiation efficiency and can achieve high power output.

The invention discloses an ultra-long-distance low-delay terahertz optical fiber ring network base station and an edge intelligent processing system, and belongs to the technical field of communication, the system realizes ultra-long-distance relay-free transmission of terahertz signals through combination of a novel terahertz quantum cascade laser and a rare earth element-doped low-attenuation special optical fiber; the signal anti-interference capability is improved by using a beam forming antenna array and QAM / PPM modulation, and the transmission reliability is ensured by a distributed optical fiber amplifier and an intelligent scheduling node. The edge intelligent processing module adopts a 7nm chip integrated acceleration unit, locally processes data in real time to eliminate return delay, and cooperates with a multi-service QoS strategy to meet the low delay demand. The system has the functions of self-diagnosis repair, standardized interface expansion, intelligent power consumption management and the like, constructs a high-reliability, low-time-delay and extensible new-generation terahertz communication network architecture, and is suitable for high-speed and low-time-delay scenes such as automatic driving, industrial control and the like.