Time-Domain Terahertz - Toptica

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Time-Domain Terahertzultrafast Lasers and a Versatile Spectroscopy SystemPhotoconductive switches (GaAs or InGaAs/InP) and organic crystals(dAST, dSTmS, oh1) represent the most common pulsed terahertzemitters. Their excitation wavelengths range from 750 nm to 1.6 μm,wavelengths easily accessible with erbium-doped femtosecondfiber lasers and optional second harmonic generation. TOPTICA’sFemtoFiber pro Tm / FemtoFiber smart Tm lasers provide superiorspecifications that fit all common emitter types.owing to the use of robust saturable absorber mirror (SAm) technologyfor mode-locking, the lasers offer turnkey operation without anymechanical alignment.The versatile TeraFlash Tm platform combines FemtoFiber smart Tm lasertechnology with state-of-the-art InGaAs antennas. The all-fiber systemattains a bandwidth above 4 Thz and an outstanding dynamic range.FemtoFiber pro IR• Wavelength 1560 nm• Power > 350 mW• Pulse width < 100 fsFemtoFiber pro NIR• Wavelength 780 nm• Power > 140 mW• Pulse width < 100 fsFemtoFiber pro IRS• Wavelength 1570 nm• Power > 180 mW• Pulse width < 40 fs
Pick one: cw or Pulsed Terahertz?Highest bandwidth with time-domain systemsTime-domain and frequency-domain techniques each have merit. Time-domain terahertz spectroscopy offers the advantage of avery broad bandwidth: spectra acquired with photoconductive switches extend to 4 Thz, and crystal emitters even achieve 10 Thz.measurement speed provides the second advantage. The acquisition of a spectrum typically takes 0.1 .. 10 seconds, depending onthe number of traces averaged. Time-domain systems also lend themselves to the investigation of multi-layered samples, where depthinformation is retrieved via time-of-flight measurements.Best resolution with frequency-domain systemsFrequency-domain spectroscopy is the preferred choice for applications requiring highest spectral resolution. While a pulsedspectrometer usually offers a resolution on the 10 Ghz level, cw systems allow frequency control with single-megahertz precision.cw systems also provide the highest dynamic ranges, with peak values greater than 80 dB. Last but not least, frequency-domainspectroscopy enables spectrally-selective measurements. It is thus possible to zoom in on one spectral signature (e.g., to measurethe strength of a single absorption line).Dynamic range of a frequency-domainsystem (left) and a time-domainsystem (right). The dips are absorptionlines of water vapor. The circleshighlight the same set of lines.Specifications cw terahertz systems Pulsed terahertz systemsBandwidth 0.05 – 2 Thz, limited by lasers 0.1 – 4 .. 10 Thz, depending on emitterPeak dynamic range ~ 85 dB ~ 75 dBFrequency resolution 10 mhz Typ. 10 GhzSpectral sensitivity yes noAcquisition time(complete spectrum)minutes to hours, depending on resolutionand lock-in timemilliseconds to seconds, depending onnumber of averagesFemtoFErb 1560• Wavelength 1560 nm• Power > 100 mW• Pulse width < 100 fsInGaAs antennas• Bandwidth > 4 THz• 1 µW average power• SM/PM fiber pigtailTeraFlash• Bandwidth > 4 THz• Peak dynamic range > 70 dB• Resolution 4 .. 40 GHz, selectable
Page 3 and 4: Terahertz WavesThe Final Frontier o
Page 5 and 6: Ceramic knife hidden behind blackde
Page 7: Frequency-Domain Terahertz Generati
Page 11 and 12: FemtoFiber pro NIRnear-Infrared Fem
Page 13 and 14: Photoconductive SwitchesFiber-coupl
Page 15 and 16: SpecificationsComponentsTeraFlashFe
Page 17 and 18: Standard PackageHigh PowerExtension
Page 19 and 20: Wide frequency tuning…The Standar
Page 21 and 22: Phase Modulation ExtensionTwin Fibe
Page 23 and 24: High power from InGaAs emittersInGa
Page 25 and 26: Customized SolutionsInnovative Answ
Page 27 and 28: Take a Look InsideTerahertz radiati

Time-Domain Terahertz - Toptica

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