Research & Development (Contract development and Consultancy)

TEM Messtechnik right from the beginning aimed at the development of special solutions for scientific and industrial applications in physics, chemistry and medicine:

Measurement and control systems Data recording and processing Diode laser systems Optoelectronics Laser stabilization High precision mechanics

The development process goes from the first idea to the production-ready solution. It includes customer specific adaption of the standard products, the development of new electronic devices, analog and digital solutions, OEM boards, modular system or stand-alone devices.

A focal point is on the high precision and fast regulators for the resonator length (or wavelength selection elements inside of the resonator) of tunable lasers and thus for the wavelength of the emitted light. The employed interferometric and spectroscopical wavelength sensors belong to the products of TEM Messtechnik as well as: PID regulators, lock-in regulators, RF modulation techniques, current sources, temperature controllers, scan generators, high voltage piezo amplifiers, photo diode amplifiers, automatic fiber couplers.

The interferometrically controlled, 1000GHz mode-hop free tuning of DFB-laser diodes is an example for these activities. Another core area is the development of control systems for positioning of laser beams (product Aligna®). The end user group ranges from those who employ the Aligna for high precision material processing to research institutions where the stabilization of the laser beam opens new experimental possibilities.

Below are examples of previous developments:

Science and Research:

Control electronics and software for laser diode spectrometers Control of laser conditioning facilities (with YAG lasers) for the age determination of rock probes Control electronics for a 3-color mixer for applications in the laser display and print technology Measurement devices for inspection of high-quality optics with the help of Phase-Shifting-Interferometry

Chemistry:

Measurement data acquisition and processing systems for probe management, integration of chemical analysis devices (like electronic scales, nuclear spin spectrographs and mass spectrographs) and control of chemical analysis devices for a chemical laboratory

Medicine:

Temperature sequencer for the melting process control of paraffin in the medical field (pathology – in cooperation with Multiblock)

Industry Production:

Brightness control for low-pressure metal vapor pressure lamps for applications in quality management and process control in industrial production processes

Energy:

Pump test station for high power pumps in power plants of energy suppliers

TV Media Production:

Control of camera cranes and remote-controlled cameras for TV and film productions

Projects

The company TEM Messtechnik participates in publicly funded research projects with cooperating partner companies, research labs and universities:

Future – Fiber-based ultrafast lasers

Development of laser systems that allow for an average power of > 10W and a pulse energy of > 1µJ with < 50 fs pulse duration.

45066 more information more information

Cooperative project: Handheld-Terahertz-Spectrometer of explosive Liquids (HANDHELD)

In the context of the tender “Detection systems for chemical, biological, radiological, nuclear and explosive hazardous substances (CBRNE hazards)”

The prevented bomb attacks to airplanes have revealed security gaps in the existing security control of flight passengers and their luggage. Until now it is very easy to smuggle explosive dangerous goods appearing as harmless liquids in conventional shampoo or beverage bottles through the control. Though sufficient to damage airplanes, the existing security controls cannot detect these liquids remotely. In addition to that, x-ray radiation is not suitable for checking persons as it is only allowed for medical purposes. For closing this security gap, new and mobile detection methods are necessary, which have to be non-destructive, contact-free and not dangerous for people, but sensitive to traces of different dangerous goods.

Usually, modern detectors are portable, hand-held, compact measuring devices, which may be produced at low cost compared to the existing detector systems.

A promising candidate for the detection of dangerous substances is terahertz spectroscopy. It uses the interaction of electromagnetic field in the terahertz frequency range with matter and returns a spectroscopic fingerprint. Special advantages of the THz radiation are its innocuousness for man and the transparency of clothes and packaging materials. It should be possible to detect and analyze explosive substances even in closed bottles.

The THz measuring technique is just at the beginning of development. For this is the reason, until now THz spectrometers are expensive, big and sensitive laboratory equipment, which are fixed to one place and need sensitive adjustment. Objects are mostly examined in transmission. So this is not a practical method for use in the security area.

The objective of this project is to develop a demonstrator of the word wide first hand-held THz spectrometer. Another aim is to expand a material data base with reference spectra of explosive liquids.

The company TEM Messtechnik GmbH contributes with the development of special fiber stretchers, including control- and modulation electronics. The completely fiber-coupled spectrometer makes the conventional free-beam delay lines unnecessary, thus reducing adjustment effort.

Support code: 13N9517
Period of the project: 01.01.2008-31.12.1012
Keywords: explosive liquids, explosive substance detection, spectroscopic detection, terahertz´-spectroscopy, femto-second laser, fast photoconductor, photoconductive antennae

Cooperative project TeraPlant: Terahertz-Measurement for In-Vivo-analysis of drought stress at economic plants

as part of the BMELV’s innovation promotion program on the subject of “Innovations for the increased use of electronics in agriculture and forestry”

The determination of the leaf water content is of high importance for numerous aspects in plant science, i.e. for basic research as well as for various aspects of applied plant biology. Due to the effects of global climatic changes leading to increasing acidification, there is a crucial need for effective tools to select drought stress resistant plants. Accordingly, remote sensing measurements of plant drought stress are actually of high scientific interest. In this context the estimation of leaf water content is inevitable.

In this project we investigate a novel method for the determination of leaf water content based on terahertz (THz) technology. As water strongly absorbs Terahertz radiation while unpolar organic material does not, we chose a transmission measurement set-up. The approach is based on an electromagnetic model of the complex THz-permittivity as a function of the water content of the plant leaf described by Jördens et al. (2009). Based on this technology, a new innovative instrument is being constructed, which can detect the water content of plant leafs in-vivo (see illustration below).

The THz radiation is generated in a photo mixing antenna that converts the optical beat note of two interfering diode lasers into THz radiation. At the detector antenna, the incoming THz radiation generates an electric current that depends on both the amplitude and the phase of the incident THz wave. This “coherent detection” allows simultaneous determination of both, the absorption of THz radiation by the water present in the sample, and the changes of the refractive index of the material passed by.

The measuring concept will be also suitable for sensors to control irrigation systems.

In-vivo-Messung des Blattwassergehalts mit Terahertz-Strahlung (BioPhotonik 1/2012)
Support code: 2815306307
Period of the project: 15.2.2008 – 1.2.2014

Sketch of a possible employment scenario for THz radiation Sketch of a possible employment scenario for THz radiation

Mode-Locking External-Cavity-Laser (MoLECL)

TEM Messtechnik GmbH was associated partner in the BMBF supported associated project MoLECL (BMF FKZ 13N 8317). The coordinator for this project was the Laserzentrum Hannover.

A laser distance sensor was developed, which bases on a new principle of measuring. In contrast to the conventional measuring procedure, the measuring surface will take part in the production laser light (illustration below). This happens, when the measuring surface forms an end mirror of the laser resonator. Special modulation of a coated laser diode as amplifier medium causes a laser pulse circulating between laser the diode and the object. The rotational frequency is a measure for the distance of the sensor to the object.

The MoLECL-measuring procedure has the advantage, that all collinear test set-ups can be realized. This procedure has a high precision with a resolution higher than 1µm and is characterized for its fast response time of smaller than 100 µs.

Through this MoLECL procedure, the following advantages can be combined in a single sensor:

Collinear measuring (low shading effect) Interferometrical resolution High measuring data rate Measuring on technical surfaces Figure: Setup of the MoLECL laser distance sensor Figure: Setup of the MoLECL laser distance sensor