Imaging
THz
The THz range lies in frequency between 300 GHz – 10 THz, in wavelength 1000 – 30 µm. Until recently, this region of the spectrum has resisted attempts to harness its potential for application, largely because of the difficulty in providing suitable radiation sources which were usually weak, bulky, and incoherent. This led to the expression ‘Terahertz Gap’ being used to describe this THz region between lower frequency, electronics-based sources (such as transistors) and higher frequency, optics-based sources (such as lasers).
The useful properties of this radiation are
- THz radiation is non-ionising, and intrinsically safe
- Many visually opaque materials are transparent to THz
- THz radiation provides a means of identification of specific materials, including biomedical materials such as DNA. This is because molecular rotations, vibrations or librations occur in this frequency range
- THz radiation also provides important information on semiconductors and metals.
Ultrashort pulse lasers are ideal sources for THz generation and detection. They can excite photoconductive switches to produce powerful THz radiation up to 7-8 THz with impressive signal to noise ratio, or induce optical rectification (DFG of frequency comb lines) in nonlinear crystals to produce THz spectra extending towards 100 THz. Here high intense pulses of several femtoseconds are advantageous.
FEMTOLASERS offers a full variety of femtosecond lasers that meet those high demanding requirements in the vast field of THz applications. You can pick from pulse energies between 1 nJ and 1 mJ or rather prefer between 100 fs down to even 7 fs pulses to uniquely engineer your THz output and detection. Any of our femtosecond lasers can be used depending on your requirements and application.
We believe to provide the most reliable light source you can expect from an ultrashort pulse laser. Our renowned and patented chirped mirror technology renders excellent pulse to pulse stabilities possible enhancing your THz signal-to-noise ratio and allows to access higher THz frequencies than any prism or fiber based lasers of comparable output. Transform limited pulses as short as 10 fs are producing THz spectra up to several ten THz by optical rectification.
In addition, FEMTOLASERS is permanently committed to customer satisfaction and product reliability. Latest innovations have released high energy oscillators providing more than 200 nJ with MHz repetition rate or single mode fiber delivery of femtosecond pulses, or very compact dispersion managing devices to keep the shortest possible pulse duration on your target.
Our customers worldwide achieve outstanding results and a remarkable number of scientific achievements, e.g. in the field of THz microscopy, broadband THz detection, fast Fourier-transform infrared (FTIR) spectrometer, imaging of biomolecules, material quality control, and biosensing with THz.
FEMTOLASERS is partner in the ambitious Teranova project which aims to harness the potential of techniques in healthcare, bioanalytics, security, process control and many other areas. Its overall objective is to create new knowledge, wealth and job opportunities that can be used for the benefit of all of Europe’s citizens.
OCT
Optical coherence tomography (OCT) is an emerging non-invasive, optical diagnostic imaging modality that enables in-vivo cross-sectional tomographic and 3-D visualization of internal microstructure in biological systems. It is analogous to ultrasound B-mode imaging except that it uses light rather than sound, therefore achieving image resolutions, approximately 10 - 100 times higher than ultrasound. Since the axial resolution is given by the coherence length, OCT imaging prefers light sources with broadest spectral bandwidths. FEMTOLASERS offers in this respect scientific and industrial based devices ideal for your applications. Scientific versions mean ultrabroad spectral bandwidth directly, i.e. without any non-linear fiber, from the Ti:S laser. These systems provide typically > 120 nm of bandwidth centered at 800 nm, delivered through a single mode fiber. Industrial/medical based systems are rugged turn-key systems used in clinical or industrial environments.
Our long year experience as light source developer is clearly shown through the achievements our renowned OCT customers worldwide have made. Advances in chirped mirror design combined with more than 10 years of experience in ultrafast laser technology allow to generate ultra stable spectra of near Gaussian shape with a bandwidth of up to 200 nm centered at 800 nm. The great bandwidth originates directly from the Titanium-Sapphire laser with unprecedented beam quality and brightness. Since no prisms for dispersion compensation and no nonlinear fibers are used you can rely on utmost stable spectral stabilities establishing themselves via near Shot noise limited figures in your measurement. In contrast to super-luminescence diodes higher output power allows deeper penetration, faster scanning, or the available power can be split for measuring numerous samples simultaneously.
Products most suited
The INTEGRAL™ OCT has been uniquely developed for its application in OCT. It is a complete turn-key femtosecond laser system appropriate for any non laser expert. Many advanced features assure absolute operation under more stringent conditions outside a laser laboratory.
FEMTOLASERS is partner of the FUN-OCT consortium. The main objective is to expand state-of-the-art OCT medical imaging capabilities to include functional information, i.e., forming a novel medical imaging platform, and to demonstrate its general feasibility in selected clinical applications that can contribute to the enhancement of quality of life and living conditions of the European aging population. The objective, or creation of an imaging platform, is realised through the development of optical ultrabroad bandwidth and ultrahigh speed tuneable light sources, optical, electronic, hard-/software designs for functional OCT, delivery systems for the envisaged medical applications and contrast agents to further enhance tomogram contrast. These developments enable unique three-dimensional real time in situ functional imaging providing unprecedented depth resolved functional tissue information that is essential to significantly improve early cancer diagnosis (skin-lung-cancer) as well as detection of retinal pathologies such as AMD and glaucoma that are worldwide leading causes for blindness.
Microscopy
Efficient excitation of chromophores is essential in non-linear microscopy (NLM), in order to obtain bright, high-contrast images. At the same time the average power deposited into the sample needs to be minimized in order to avoid adverse effects as functional modifications and damage. Employing shorter excitation pulses is beneficial for NLM in both these respects, since the excitation efficiency increases linearly with decreasing pulse duration.
Ultrashort (sub-20-fs) pulses at a center wavelength of 800 nm are particularly well suited for NLM since their spectrum covers most wavelength regions of interest ranging from <700 nm="" to="" eventually="">1 micron. Combining FEMTOLASERS' state-of-the-art oscillators with the all-dispersive-mirror dispersion compensation modules MOSAIC™ allows undistorted delivery of sub-20-fs pulse at the sample via complex scanning microscopes. Efficient excitation of a wide range of chromophores becomes possible at unprecedentedly low average powers levels.
Most suited products are the oscillators INTEGRAL™ and FUSION™, the MOSAIC™ dispersion management module and our patented optics line eg. reflectors and beam splitters.
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