Time-Domain Terahertz - Toptica

Phase Modulation ExtensionTwin Fiber Stretcher with HV Drivercw terahertz spectroscopy based on photomixing offers the attractive feature ofdetecting both amplitude and phase of the terahertz wave. Determining the phaserequires a modulation of the optical path length, or of the terahertz frequency. ThePhase Modulation Extension provides a fast and accurate technique to scan theterahertz phase by using a symmetric setup with two fiber stretchers wound aroundpiezo actuators. The twin-fiber concept not only doubles the modulation amplitude, butalso increases the thermal stability of the setup.The Phase Modulation Extension is available at 850 nm and 1550 nm. It perfectly fits theStandard Package 850 / TeraBeam 1550, and the Spectroscopy Extensions.Specifications THz Phase Mod / 850 THz Phase Mod / 1550ConceptWavelengthDifference frequency tuningDifference frequencyresolutionFibersTwin fiber stretcher with piezo actuators853 + 855 nm, definedby Standard Package*1546 + 1550 nm,defined by TeraBeamCf. Standard Package or TeraBeamCf. Standard Package or TeraBeam,Complete amplitude + phase informationat maximum resolution2 x 60 m, SM/PM fibersKey features· Fast and accurate modulation of theterahertz phase· Twin fiber stretcher with piezoactuators and HV driver· Path length modulation up to 3 mm@ 1 kHzApplications· High-resolution frequency-domainspectroscopy· Phase-sensitive terahertzmeasurements at fixed frequency(e.g., for imaging)Max. path length modulationHV driver3 mm @ 1 kHzIncludedSoftwareIncluded, part of control programDFB laser #1* Customized wavelength ranges on requestNormalized photocurrent1.00.50.0-0.5-1.0Delay stageFiber stretcher0 1 2 3 4Path length change (mm)Terahertz photocurrent, measuredwith fiber stretchers (red circles) or amechanical delay stage in the terahertzpath (black squares). The delay-stagescan deviates from a cosine fit due tostanding waves. The fiber-stretcherscan yields a perfect cosine curve.DFB laser #2Schematic of Standard Package (green)with Phase Modulation Extension (red).Order informationTHz Phase Mod / 850THz Phase Mod / 1550Twin fiber stretcher for terahertz phase modulation,850 nmTwin fiber stretcher for terahertz phase modulation,1550 nmNote: The Phase Modulation Extension requires a set of seed lasers(e.g., the Standard Package SYST THz STD / 850, or the TeraBeam 1550).Combination with the High Power Extension is recommended.www.toptica.com | 21