We demonstrate the first lasing emission of a thermoelectrically cooled terahertz quantum cascade laser thz qcl. Linfield2 1harvard school of engineering and applied sciences, harvard university, cambridge, ma 028 2school of electronic and electrical engineering, university. Its operation is based on 3quantumwell 3qw modules, where the gaas qws are separated by al 0. The qcl is the most mature source of coherent farinfrared emission from 60 to 250 um, i. Modeling and experiments yao chen et aloptimization of thz semi. The sideabsorbers consist of a top metalization setback with respect to the laser ridge and an additional lossy metal. Terahertz differencefrequency quantum cascade laser. Algaasgaas terahertz quantum cascade laser with goldbased. Beat notes are detected with a gaas diode mixer and a microwave spectrum analyzer, permitting very precise. Terahertz quantum cascade lasers quantum cascade lasers qcl are electricallypumped semiconductor lasers based on intersubband transition in the conduction band of the heterostructure. Population inversion and laser emission can be freely engineered. Pdf we present a terahertz quantum cascade laser operating on a thermoelectric cooler up to a recordhigh temperature of 210. Thz radiation was outcoupled through the midir waveguide facets. Gain dynamics in a heterogeneous terahertz quantum cascade.
Terahertz quantumcascade transmissionline metamaterials. Foremost among these developments has been the thzfrequency quantumcascade laser qcl 3,4 a compact, electrically pumped source. Highspeed modulation of a terahertz quantum cascade laser by. Injection locking of a terahertz quantum cascade laser to a telecommunications wavelength frequency comb joshua r. The terahertz thz frequency quantum cascade laser qcl is a compact source of thz radiation offering high power, high spectral purity and moderate tunability. A lamb dip with a subdoppler linewidth of 170 khz is observed for a rotational transition of hdo. Pdf thermoelectrically cooled thz quantum cascade laser. Frequency stabilization of a thz quantum cascade laser qcl. Algaasgaas terahertz quantum cascade laser with gold. We report on the engineering of broadband quantum cascade lasers qcls emitting at.
Terahertz quantum cascade laser leiying ying, noriaki horiuchiikeda and hideki hirayamarecent citations transmission electron microscopy of algaasgaas quantum cascade laser structures t. The spectral gain of a multistack terahertz quantum cascade laser, composed of three active regions with emission frequencies centered at 2. Terahertz quantumcascadelaser source based on intracavity. Quantum cascade lasers qcl are semiconductor lasers that emit in the mid and longwave ir bands, and are. Pdf dopplerfree spectroscopy with a terahertz quantum. We present the experimental study of the direct emission detection system based on the thz quantum cascade laser as a source and hot electron bolometer heb detector in view of its application as an optical communication system. Slingerland p, baird c and giles r h 2012, application of multisubband selfconsistent energy balance method to terahertz quantum cascade lasers, semicond. This experiment demonstrates that the quantum well photodetector is potentially useful for reflection imaging applications. Diode laser thz qcl rf optical spectrum analyzer dc bias.
In a quantum cascade laser, the mentioned quantum well structure is embedded in a waveguide, and the laser resonator is mostly of dbr or dfb type. In the best devices, the operating temperature has reached 200 k in pulsed mode and 129 k in continuous wave cw mode. The theoretical calculation of a boundtocontinuum quantum cascade at 3. Osa injection locking of a terahertz quantum cascade laser. In this dissertation we present the complete realization of semiconductorheterostructure lasers emitting in the thz and employing the quantum cascade technology. Thz source publications submillimeterwave technology. Terahertz nanoscopy of plasmonic resonances with a quantum. Terahertz quantum cascade laser qcl sources based on intracavity difference frequency generation are. Gain dynamics in a heterogeneous terahertz quantum cascade laser.
We report on the dopplerfree saturation spectroscopy of a molecular transition at 3. The broadband response of the device was characterized by using thz timedomain spectroscopy, and the modulation characteristics such as the modulation depth and cutoff frequency were studied with a 2. Although the quantum cascade gain medium can be used to produce incoherent light in a superluminescent configuration, it is most commonly used in combination with an optical cavity to form a laser. Osa terahertz quantumcascade lasers as highpower and. Qclasers are the longest wavelength semiconductor laser. The quantum cascade laser as a terahertz local oscillator. The homemade ssnom, based on a resonant tuning fork and metallic tip, operates in tapping mode with a spatial resolution of.
The reported technique is able to control and fully suppress higher order lateral modes in broadband terahertz quantum cascade lasers by introducing sideabsorbers to metalmetal waveguides. As such, these sources are particularly suited to the application of thz frequency imaging across a range of. The overall response is described by parallel contributions from the recti. Since its invention in 2001, the thz quantum cascade laser qcl has emerged as a compact semiconductor thz source capable of delivering milliwattlevel power or higher at various frequencies from 1. Terahertz quantum cascade laser sources based on intracavity frequency mixing are currently the only monolithic electrically pumped semiconductor devices that can operate in the 16 thz spectral range at room temperature. Towards the bigger goal of realizing an active terahertz metamaterial to ultimately develop zeroindex terahertz quantumcascade lasers immune to spatial hole burning, or. The introduction of the cherenkov waveguide scheme in these devices grown on semiinsulating inp substrates enabled. Terahertz thz quantum cascade lasers sciencedirect. Evaluation of material systems for thz quantum cascade laser active regions hermann detz, aaron m. Osa imaging with a terahertz quantum cascade laser.
Pdf dispersion in a broadband terahertz quantum cascade laser. Thz quantum cascade lasers for standoff molecule detection. It was in october of 2001 that the first qc laser with a photon energy less than the semiconductor optical phonon energy was demonstrated at 4. This is the simplest of the quantum cascade lasers. However, for many applications, a radiation source with a continuous coverage of a substantially larger frequency range is required. Terahertz sidebandtuned quantum cascade laser radiation. Freeman, lalitha ponnampalam, haymen shams, reshma a. Thz quantum cascaded lasers qcl are high power solidstate electrically driven coherent light sources that span 15 thz 420 mev, 60300 m. A terahertz quantum cascade laser qcl uses electron transitions between manmade quantum well levels to emit terahertz.
Pdf two terahertz quantum cascade lasers based on gaasal0. Terahertz differencefrequency quantum cascade laser sources. The terahertz thz frequency quantum cascade laser qcl is a compact source of thz radiation offering high power, high spectral purity and. Recent progress in terahertz differencefrequency quantum. Longterm frequency and amplitude stability of a solidnitrogencooled, continuous wave thz quantum cascade laser pdf 162. Quantum cascade lasers qcls are novel semiconductor devices. Liu, terahertz quantum cascade lasers operating up to 200 k with optimized oscillator strength and improved injection tunneling, opt.
We have measured the spectral linewidths of three continuouswave quantum cascade lasers operating at terahertz frequencies by heterodyning the freerunning quantum cascade laser with two farinfrared gas lasers. We present a terahertz thz scattering nearfield optical microscope ssnom based on a quantum cascade laser implemented as both source and detector in a selfmixing scheme utilizing resonant quartz tuning forks as a sensitive nanopositioning element. Evaluation of material systems for thz quantum cascade. Evaluation of material systems for thz quantum cascade laser. Pdf thz communication system based on a thz quantum cascade. Kainz, sebastian schonhuber, tobias zederbauer, donald macfarland, michael krall, christoph deutsch, martin brandstetter, pavel klang, werner schrenk, karl unterrainer, and gottfried strasser. Linfield, injection locking of a terahertz quantum cascade laser to a telecommunications wavelength frequency comb, optica 4, 10591064 2017. Sirtori materiaux et phenomenes quantiques, universite paris 7 denis diderot. Dopplerfree spectroscopy with a terahertz quantumcascade laser.
The terahertz thz region of the electromagnetic spectrum is usually defined as ranging from 1 thz 300 micrometers in wavelength to 10 thz 30 micrometers in wavelength. Terahertz sidebandtuned quantum cascade laser radiation andriy a. Semiconductor terahertz lasers based on the quantum cascade design, so called terahertz quantum cascade lasers thz qcls, have become an established thz technology. We investigate the lightcurrentvoltage characteristics and emission spectra of 2. Highspeed modulation of a terahertz quantum cascade laser. In this chapter, we report the fabrication of al 0. Pdf phaselocking a thz quantum cascade laser to a thz. Terahertz quantumcascade laser with active leakywave.
Pdf dispersion in a broadband terahertz quantum cascade. A high temperature threewell thz qcl emitting at 3. A qcl is built by stacking up alternating layers of semiconductors with thicknesses of only a few atoms. Thz quantum cascade lasers with wafer bonded active regions m. Williams, hans callebaut, sushil kumar, and qing hua department of electrical engineering and computer science and research laboratory of electronics, massachusetts institute of technology, cambridge, massachusetts 029 john l. Terahertz quantumcascade lasers qcls have now been demonstrated at frequencies of 1. Nixon4 1 submillimeterwave technology laboratory, dept. Distinct regions of brain tissue rich in fat, proteins, and fluidfilled cavities are resolved showing the. This chapter is dedicated to terahertz thz quantum cascade laser technology. Reflection imaging with terahertz quantumcascade laser. The powercurrent relation and emission spectrum of this laser are shown in fig. Pdf thermoelectriccooled terahertz quantum cascade lasers. The energy levels in a quantum cascade laser are formed by quantum mechanically bound states in an artificially grown semiconductor nanostructure.
The lasers active region is build by stacking the 228 modules. A quantum cascade laser qcl is a nextgeneration device that uses electron transitions between manmade quantum well levels, as opposed to traditional lasers that use transitions between atomic levels. Phaselocking a thz quantum cascade laser to a thz comb through an alloptical beating. A reflection imaging system based on the terahertz quantum well photodetector is presented. Terahertz quantumcascade laser with active leakywave antenna amir a. Foremost among these developments has been the thzfrequency quantumcascade laser qcl 3,4 a compact, electrically pumped source based on intersubband transitions in a quantum heterostructure. Bacon, timeresolved pumpprobe investigation of the terahertz quantum cascade laser, ph.
Terahertz quantum cascade lasers with copper metalmetal. Terahertz frequency quantum cascade lasers thz qcls are compact, semiconductor sources of coherent thz radiation, and have numerous potential applications in chemical sensing and industrial. Unlike ordinary band gap lasers known from everyday life laser pointers, bluraydvdcd drives, they are using a radically new concept. Six years after their birth, terahertz quantumcascade lasers can now deliver milliwatts or more of continuouswave coherent radiation throughout the terahertz range the spectral regime. Using this technique the first demonstration of beam scanning for a terahertz qclaser was reported from 35. The operation of thz quantum cascade laser in the region of. Goodhue 1photonics center, department of physics and applied phys ics, university of massachusetts lowell, lowell, massachusetts 01854, usa. Quantum cascade lasers rp photonics consulting on laser. Since then qc lasers have become the dominant midinfrared semiconductor laser sources, with spectral coverage from wavelengths of.
Pdf thz communication system based on a thz quantum. The purpose of this study was to determine the lasing frequency in thz when altering which of two wells were doped. Terahertz thz frequencies, which exploit a heterogeneous active region. Grapheneintegrated metamaterial device for allelectrical. We demonstrate biomedical imaging using a terahertz quantum cascade laser. We found that a certain level of external optical feedback is tolerable as long as the free spectral range of. Williams submitted to the department of electrical engineering and computer science on august 22, 2003, in partial ful. Pdf phaselocking a thz quantum cascade laser to a thz comb. Linewidth and tuning characteristics of terahertz quantum. Terahertz thz quantum cascade lasers qcls are powerful radiation sources for highresolution and highsensitivity spectroscopy with a discrete spectrum between 2 and 5 thz as well as a continuous coverage of several ghz. Reno, and qing hu, towards thz dualcomb spectrometer based on quantum cascade laser frequency combs, itqw2015, the th international conference on intersubband transitions in quantum wells, vienna, austria, september 611 2015. The terahertz thz quantum cascade laser1 qcl is a compact and coherent source of thz radiation, which is a unipolar device based on intersubband transitions in the conduction band of a speci. This new optoelectronic source of coherent terahertz radiation allows building a compact imaging system with a large dynamic range and high spatial resolution.
Hu department of electrical engineering and computer science, and. Terahertz quantum cascade lasers with copper metalmetal waveguides operating up to 178 k mikhail a. Injection locking of a terahertz quantum cascade laser to. The first qc laser was demonstrated at the much shorter wavelength of 4. Introduction last year marked the 20th anniversary of the invention and demonstration of the quantum cascade laser qcl at bell laboratories 1. Boreiko center for astrophysics and space astronomy, ucb 593, university of colorado, boulder, colorado 80309 b. Rp photonics encyclopedia quantum cascade lasers, qcl. What is the effect of doping locations on lasing frequency. Foremost among these developments has been the thz frequency quantum cascade laser qcl 3,4 a compact, electrically pumped source based on intersubband transitions in a quantum heterostructure. A an introduction to quantum cascade lasers qcls april, 20 page 1 what is a qcl. There are also externalcavity lasers, where a wavelength tuning element such as a diffraction grating is part of the resonator. Reflected terahertz imaging of a logo on a universal serial bus usb flash disk is demonstrated.
1252 157 691 1253 853 328 392 132 98 1311 258 1355 30 1165 746 25 1087 1177 916 866 73 517 1087 369 1372 778 113 769 1241 983 1359 1300 423 504