The Standard Package offers the essential laser equipment for difference frequency generation in the terahertz range. It comprises two DFB lasers, fiber-optic beam combination, and driver electronics. The package is complemented by the TeraControl unit TC 110, an FPGA-based module for computerized frequency tuning, and digital lock-in detection of the terahertz photocurrent. – The Standard Package is available at 850 nm and 1550 nm.
- Maximum laser power at extrema of DFB tuning range
- Includes BoosTA 850 nm or 1550 nm Er:fiber amplifier
- Fiber input and output ports
- Requires Standard Package
- Bandwidth and resolution as in Standard Package
The High Power Extension employs TOPTICA’s established semiconductor amplifier technology (BoosTA™). The two-color output of the Standard Package is amplified and coupled into a 50:50 % fiber-optic splitter, providing the required laser beams for terahertz generation and detection. A 1550 nm version is also available, employing an Erbium-doped fiber as gain medium.
CW Terahertz: Phase Modulation Package
- Fast and accurate modulation of the terahertz phase
- Twin fiber stretcher with piezo actuators
- Enhanced thermal stability due to dual-fiber concept
- Requires Standard Package and Spectrosc. Extension
- Combination with High Power Extension recommended
Cw terahertz spectroscopy based on photomixing offers the attractive feature of detecting both amplitude and phase of the terahertz wave. Determining the phase requires a modulation of the optical path length, or the terahertz frequency. The Phase Modulation Package offers a particularly fast and accurate technique to scan the terahertz phase, by using a symmetric setup with two fiber stretchers
Available at 850 nm and 1550 nm, the Spectroscopy Extension employs the latest GaAs or InGaAs photomixer technology. The package has two versions with different levels of integration. The basic version features two fiber-pigtailed photomixers and a transimpedance ampliﬁer. The second, or complete version, additionally includes positioning stages and off-axis parabolic mirrors. The system is conveniently controlled from a standard laptop or PC.
The TeraScan systems are “TopSeller” configurations for cw-terahertz spectroscopy. The TeraScan 850 is based on GaAs photomixers and offers an outstanding bandwidth and dynamic range. The TeraScan 1550 employs InGaAs antennas and provides the most compact spectroscopy platform. Both systems feature TOPTICA’s proprietary TeraControl module for computerized frequency tuning and data acquisition, and an intuitive software interface.
Terahertz science is a vibrant and exciting field of research. The number of applications is steadily growing, and so are the requirements on the utilized laser systems. And sure enough, a “Standard Package” may need to be modified into a “Non-Standard Package” if photomixers are to be cooled to liquid-Helium temperatures, or if terahertz frequencies outside the lasers’ tuning range are to be attained. And even an “Extended Spectroscopy Kit” might call for a further extension, if the beam is to be focused onto a microscopic sample.
Our product specialists have many years of hands-on experience with diode lasers and terahertz systems, and will be able to react flexibly to our customers’ needs. Examples of custom-designed terahertz systems that we have built thus far include:
- Tuning range extensions. The frequency span of a cw terahertz spectrum is usually limited by the tuning range of the DFB diode lasers. Adding a third diode laser greatly enhances the accessible frequency range. With carefully selected center wavelengths of our DFB lasers, we have pushed the bandwidth of a 1550 nm TeraBeam + Spectroscopy Kit to beyond 2 THz.
- Non-standard wavelengths. TOPTICA’s portfolio of DFB lasers covers, without exception, all wavelengths between 760 nm and 2900 nm. Thus, if an application requires a seed wavelength other than 850 nm or 1550 nm – e.g. for research on “exotic” photomixer materials, or for cryogenic experiments, where the temperature-induced change of the photomixers’ band-gap needs to be taken into account –, we will be happy to work out the matching laser configuration.
- High-precision frequency control. Ultimate spectral resolution is achieved by combining the lasers of the Standard Package with our patented iScan quadrature interferometer. The frequency of each laser is adjusted with an accuracy of ~ 1 MHz. This translates directly into resolution of the terahertz signal, making our systems well-suited for even the most challenging measurement tasks in low-pressure gas spectroscopy.
- Advanced terahertz optics. We are happy to provide customized optics assemblies, e.g. with a focused terahertz beam, or even a versatile setup that permits simple and reproducible switching between transmission and reflection-mode measurements.