9 results about "Terahertz quantum cascade laser" patented technology

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 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.

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 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.