We present a spectral domain refractive low coherence interferometry technique (SD-rLCI) using a novel extreme
broadband Super Continuum laser source equipped with a dual spectrometer system which is able to measure the
dispersion in the visual and near infrared range simultaneously. The setup was verified obtaining the second order
dispersion of distilled water. We will use this system for measuring the dispersion sensitivities of important tissue
substances in order to determine analyte concentrations within mixtures.
A THz time domain imaging system is optimized and analyzed with ZEMAX. The requirements to the optical design of
time domain imaging systems in the THz spectral region are deduced. A system is presented, which is diffraction-limited
for wavelengths down to 838 μm and field points up to ±4 mm. In the optical system a 90° off-axis parabolic mirror is
combined with an aspheric plastic lens. The lens was made from ZEONEX E48R®, and it was manufactured by ultraprecision
machining. A resolution test of the system shows that on time domain analysis of the pulse maximum on-axis 1 LP/mm can be resolved with an intensity contrast of 0.22. The resolution of the outermost field point is 0.67 LP/mm with an intensity contrast of 0.23. An outlook of an optimized system for imaging a field of ±10 mm in x- and y-direction
The applicability of moth-eye structures to THz components is investigated. With the help of RCWA and effective medium theory, optimal structural parameters for one-dimensional and two-dimensional periodical surface-relief gratings are deduced. The required structural parameters are in such order of magnitude that they can be manufactured by ultra-precision machining directly into the surface of the substrate material. Benefiting is that plastic materials, which are preferred materials in THz spectral region, can be accurately manufactured by ultra-precision machining. The application of the moth-eye structures follows directly the primary shaping of the components by conventional manufacturing methods like turning and milling so that no additional materials are necessary. A comparison between several structures fabricated on planar plastic probes is given.
InN, a novel semiconductor material, is used as THz surface emitter. The material is irradiated with fs-laser pulses at 1060 nm and 800 nm and the emitted ultrashort THz pulses are measured by phase sensitive detection. Pulsforms, amplitudes and spectra are compared to the THz emission of p-doped InAs, the standard material for THz surface emission.