The ARYELLE Butterfly is a highly advanced Double-Echelle spectrograph from LTB Lasertechnik Berlin and part of the ARraY echELLE product family. Developed from a specialized concept, it integrates two spectrally separated ARYELLE 400 spectrometers within a single compact and thermally stable enclosure. Its distinctive architecture sequentially projects two two-dimensional echelle spectra onto a shared detector, helping reduce overall system costs while maintaining a compact footprint and delivering exceptional spectral performance.
Optical Design and Performance
The system is engineered for maximum flexibility across the Vacuum-UV (VUV), ultraviolet (UV), visible (VIS), and near-infrared (NIR) spectral regions. Each spectrometer wing features a 400 mm focal length and an f/10 opening ratio, providing high light throughput. The optical configuration incorporates high-quality echelle gratings, CaF2 prism-based order separation, precision imaging optics, and narrow input slits.
The dual-spectrometer design allows wavelength coverage and spectral resolution to be customized for specific scientific and industrial requirements. Typical configurations achieve spectral resolutions of up to 50 000 in the 175 nm to 330 nm VUV range and between 15 000 and 30 000 in the 330 nm to 850 nm UV-VIS-NIR range. A large 27 x 27 mm2 detector area supports a wide selection of modern CCD, sCMOS, and ICCD detectors.
Precision and Operational Stability
Chromatic aberrations are minimized through the extensive use of reflective optics with broadband UV coatings and CaF2 prisms. Light can be coupled through an SMA fiber for UV-VIS-NIR measurements or through dedicated reflective transfer optics for VUV applications below 200 nm, where conventional fibers experience significant transmission losses.
For long-term accuracy, the instrument includes an internal shutter and an integrated calibration lamp. These features enable fully automatic wavelength recalibration during operation, making the system particularly valuable for extended measurements and industrial process monitoring.
Software and Data Analysis
LTB’s Sophi nXt software manages spectrometer and detector functions while controlling the complete measurement workflow. After wavelength assignment, spectral lines are automatically evaluated using an integrated database containing more than 50 000 entries. When possible, detected lines are identified and linked to their corresponding elements. Users can modify and expand the database, which is based on the Strong Lines of the NIST Spectra Data Base. Automatic calibration is performed quickly and efficiently using the included calibration lamp.
