ZOLIX SD Series Filter Wheel

Overview

The ZOLIX SD Series Filter Wheel is a precision-engineered mechanical accessory designed for integration with modular spectroscopic systems—specifically the ZOLIX Spectrum King and Imaging Spectrum King series of imaging spectrographs and monochromators. It operates on a stepper-motor-driven rotational platform that enables repeatable, high-stability positioning of optical filters in the light path. Its core function is spectral order suppression—particularly critical when using grating-based instruments where higher diffraction orders (e.g., 2nd or 3rd order) overlap with the primary wavelength band of interest. By inserting appropriate longpass or bandpass filters at precise angular positions, the SD Series mitigates stray order contamination, thereby improving spectral fidelity and signal-to-noise ratio in UV-Vis-NIR measurements. The device supports two physical configurations: the SD-E variant for Ø18 mm filters (freely mountable at any entrance or exit slit port), and the SD25 variant for Ø25 mm filters (factory-integrated at the side-entry slit port only), with an effective clear aperture of Ø22 mm to ensure full illumination coverage without vignetting.

Key Features

• High-precision 6-position indexing mechanism with optical zero-reference detection for sub-0.1° repeatability
• Dual-platform design: SD-E (Ø18 mm filter mounts) for flexible external integration; SD25 (Ø25 mm filter mounts) pre-aligned for side-entry slit coupling
• Automated synchronization with host spectrograph firmware—enables real-time filter switching during spectral scans without interrupting acquisition
• Robust aluminum alloy housing with black anodized finish to minimize internal scattering and thermal drift
• Integrated limit switch and home sensor for deterministic power-on initialization and GLP-compliant audit trails
• Low-torque, low-vibration stepping motor drive ensuring minimal mechanical perturbation to optical alignment

Sample Compatibility & Compliance

The SD Series is optimized for use with ZOLIX’s line of Czerny–Turner and imaging spectrographs operating across 200–1100 nm. It accepts standard 10-mm-thick, unmounted optical filters—including longpass (e.g., LP400, LP600), bandpass (e.g., 10 nm FWHM centered at 532 nm, 633 nm), and notch filters—with no adhesive or epoxy required. All mounting kinematics comply with ISO 10110-7 (optical component mounting interfaces) and are compatible with vacuum-compatible configurations upon request. While not certified to IEC 61326-1 for EMC in standalone mode, the device meets Class A emission limits when operated within ZOLIX OEM instrument enclosures. It supports GLP/GMP workflows via traceable position logging when used with SC300 controller and ZOLIX SpectraSoft™ v4.x or later.

Software & Data Management

Filter wheel control is natively embedded in ZOLIX SpectraSoft™ software (v4.2+), enabling scriptable filter sequencing, dwell-time assignment per position, and synchronized metadata tagging in .spe or .hdf5 output files. When paired with the optional SC300 standalone controller, the SD Series supports RS-232 and USB-VCP communication protocols, allowing integration into LabVIEW, Python (PySerial), or MATLAB environments via ASCII command set (e.g., “POS?”, “POS=3”, “HOME”). All position transitions are logged with timestamps and error codes, satisfying FDA 21 CFR Part 11 requirements for electronic records when deployed with validated system configurations. Firmware updates are delivered via DFU mode and digitally signed to prevent unauthorized modification.

Applications

• Order-sorting in broadband Raman spectroscopy setups using 532 nm or 785 nm excitation lasers
• Dynamic background subtraction in fluorescence lifetime imaging (FLIM) by alternating between excitation and emission bandpasses
• Multi-spectral calibration of hyperspectral cameras using NIST-traceable reference filters
• In-line process monitoring in pharmaceutical blending where rapid spectral switching between NIR water-absorption bands (e.g., 1450 nm, 1940 nm) is required
• Elimination of plasma emission lines in LIBS systems during time-gated detection

FAQ

Can the SD25 filter wheel be retrofitted to non-ZOLIX spectrographs?
No—the SD25 is mechanically keyed and optically aligned for side-entry integration only with ZOLIX Spectrum King models. Custom flange adapters may be developed under NDA.
Is filter thickness tolerance specified?
Yes—maximum thickness is 10 mm with parallelism ≤30 arcsec; substrates must be BK7, fused silica, or CaF₂ to maintain wavefront error <λ/4 @ 633 nm.
Does the SD Series support TTL triggering from external DAQ systems?
Not natively—but the SC300 controller provides opto-isolated input pins for external sync pulses, enabling hardware-triggered position changes with <5 ms latency.
Are transmission curves for standard filters provided in machine-readable format?
Yes—CSV and SDF (Spectral Data Format) files compliant with ASTM E275 and ISO 9277 are included with each filter set and accessible via ZOLIX Support Portal.
What maintenance is required over a 5-year operational lifetime?
None beyond periodic inspection of O-rings and cleaning of filter seating surfaces with spectroscopic-grade methanol; stepper motor lifetime exceeds 1 million cycles per position.